Ok, well there's been a lot of debate going on about what jobs are better than other jobs. For example, what is the best tank? What melee tanks best. The best answer is "that it is dependant on the situation." But I guess that answer is lacking in detail and therefore leaving many to question the nature of what works best, why exp varies from party to party and, what their own job is.
So I will explain as I best can in my own personal opinion, in what I think(in no way attempting to sound arrogant) a fairly considerable amount of time in EXP PTs.
The first thing you want to do is to classify what each party desires.
The standard is... 3 melee jobs, 3 support/mage type jobs. I will give some examples of well rounded parties...
NIN THF RNG BLM WHM RDM.
PLD DRK SAM BRD WHM BLM
WAR THF MNK RDM WHM BLM
There are parties with special setups that work under special circumstances.
PLD BLM BLM BLM BLM BRD
SMN SMN SMN SMN SMN BRD
NIN NIN THF THF BRD WHM
The three listed above will not be mentioned, as they are not the standard type of party I am attempting to promote. Do they work for good exp, yes. Will you be able to assemble them often. Nope.
This discussion is most often met with...
"It's the player's skill that matters not the job."
It's true that a bad mind can thwart a flawlessly assembled party, I'm sure it's happened to all of you. But unfortunately, all jobs have limits, and what's good to know is, how do certain jobs compensate for each other's limits?
Let's take a look at the three standard tanks: Paladin, Warrior and Ninja. PLD WAR NIN
Let's assume all players are playing their jobs correctly(as I see it).
The Paladin holds hate best. He does little damage. If he has a constant MP recovery line, he supports the continued chain by healing himself and lessening the load on the WHM'S MP. A paladin must be compensated by strong, high damage jobs in their party. A paladin can protect them. For example... BLM. Paladin does less damage than WAR. But holds more hate. BLM's damage is only limited by the tanks ability to hold hate. Hence, equilibrium.
The Warrior does the most damage. He will take less damage than PLD with Nin sub on slower attacking mobs. He will however require the most amount of healing from the WHM. He will have trouble holding hate unless accompanied by THF. A good job to party with WAR is DRG. To understand this is to understand the nature of the WAR tank and the nature of the DRG. Even with the wyvern's damage, a DRG will never rival a DRK for damage, however, because of the wyvern, the hate is spread among the two. Allowing the DRG to accumulate more damage than others and not remove hate from WAR. DRG with PLD on the other hand is a waste, because it's not needed.
The Ninja does more damage than paladin, but to be honest, Ninja damage isn't anything to write home about. They are good because they just don't take too much damage post 37. Pre 37 they are an akward tank, often requiring assistance from another melee. Remember though that damage translates into hate loss, so by blinking damage away, they can hold hate. With offensive ninjutsu, they can also build some hate too. They are often the tank of choice among more experienced, but they are extremely expensive to maintain properly.
The support roles can be looked at from the following jobs: WHM RDM BLM SMN BRD
But any 3 of them randomly chosen will not always work, especially depending on your choice of tank. I would say, for the most part, you want a RDM in there with a PLD. Refresh is a single target spell, and Ballad is not. Most PLD don't get Ballad during the actual fight and it makes holding hate a difficulty. It can certainly work, but, all things must be compensated accordingly. Maybe a THF in the PT at that point would be a good idea, even when usually it's a bad choice for PLD, as you need DDs capable of compensating thelr low damage capability. BRD and RDM work well together, but not with a WAR tank unfortunately. With PLD that means they get to be their own main healer, and have total control of mob. With Nin that's just fine becuase rdm can heal for nin as they get so little damage. War however require too much outside healing and need a WHM.
So... PLD want a RDM. WAR need a WHM.
Until level 25, you want two healers if you intend to chain effectively. WHM and WHM works, but if the RDM is good, WHM and RDM is actually better. The usefulness of RDM pre-level 41 when they can refresh is solely determined by the ability of a person to understand what that RDM is. What you are is... above all, a support healer to help continue the chain. You debuff, you dispell, all for the purpose of continuing the chain. Getting refresh is only the crowning glory on your job. But if you think your job is to whack the mob with your sword for 3 damage a pop, you are leading your job towards uselessness.
At level 25, WHM and BRD is preference. If RDM wants a spot they yet again, must understand their job. Once you hit 41 you go into the more standard combinations as described.
WHM RDM BLM is the standard. It's time tested. It works. Of course a SMN can replace either the BLM or WHM, but for main healing a WHM is preferable. As for replacing the BLM, it's about damage dealing. Do they have fenrir? Can their buffs translate to more damage than BLM's nuking. It's... iffy. At higher level, they are like DRGs are to DRK. High damage output without any hate. I think maybe WAR DRG DRG SMN WHM RDM works nicely... SMN can do intense damage and WAR will hold hate. At lower levels, SMN will be most usually main healer. Sometimes their aeriel armor is useful with pld tank, because the other tanks already can blink themselves. Stoneskin always great, especially for war tank, or the ocasional crazy ranger. However, don't replace BLM with SMN unless there's a DRK for stun or you know that stun won't be needed. If there's no blm, remember that unless someone has a 29+ BLM sub, no escape either.
As for the DDs. The party setup matters, but so does the zone you'll be fighting in. Are you gonna fight bones? Get a monk. Fighting flies, you would be well off with a THF. Some level up a secondary weapon to use for two purposes. Certain weapons are best on certain mobs, and certain weapons chain better with other weapons. Take the skillchain into account. Take a strong ending WS into account. Are you gonna fight crabs, can you do distortion? So often parties will form not taking this into account, and act once the exp is slow as if this was unpreventable. All these things have a huge bearing on your XP, so try to take them into account. It's handy for you to have an alternative weapon for exp pt as a DD, but... remember to have your standard present, as, well... you might have been invited with a certain skillchain in mind.
All this being said, maybe you can't find the right jobs to put together your perfect party. Is your party going to be at least decent? Are you wasting everyones time by assembling a piece of junk? Until an at least capable party is possible to assemble, go try something else. Fish, raise your cooking, level another job that's more needed at that moment. Please just don't force it. Don't make deadlines on your character's exp.
So I will explain as I best can in my own personal opinion, in what I think(in no way attempting to sound arrogant) a fairly considerable amount of time in EXP PTs.
The first thing you want to do is to classify what each party desires.
The standard is... 3 melee jobs, 3 support/mage type jobs. I will give some examples of well rounded parties...
NIN THF RNG BLM WHM RDM.
PLD DRK SAM BRD WHM BLM
WAR THF MNK RDM WHM BLM
There are parties with special setups that work under special circumstances.
PLD BLM BLM BLM BLM BRD
SMN SMN SMN SMN SMN BRD
NIN NIN THF THF BRD WHM
The three listed above will not be mentioned, as they are not the standard type of party I am attempting to promote. Do they work for good exp, yes. Will you be able to assemble them often. Nope.
This discussion is most often met with...
"It's the player's skill that matters not the job."
It's true that a bad mind can thwart a flawlessly assembled party, I'm sure it's happened to all of you. But unfortunately, all jobs have limits, and what's good to know is, how do certain jobs compensate for each other's limits?
Let's take a look at the three standard tanks: Paladin, Warrior and Ninja. PLD WAR NIN
Let's assume all players are playing their jobs correctly(as I see it).
The Paladin holds hate best. He does little damage. If he has a constant MP recovery line, he supports the continued chain by healing himself and lessening the load on the WHM'S MP. A paladin must be compensated by strong, high damage jobs in their party. A paladin can protect them. For example... BLM. Paladin does less damage than WAR. But holds more hate. BLM's damage is only limited by the tanks ability to hold hate. Hence, equilibrium.
The Warrior does the most damage. He will take less damage than PLD with Nin sub on slower attacking mobs. He will however require the most amount of healing from the WHM. He will have trouble holding hate unless accompanied by THF. A good job to party with WAR is DRG. To understand this is to understand the nature of the WAR tank and the nature of the DRG. Even with the wyvern's damage, a DRG will never rival a DRK for damage, however, because of the wyvern, the hate is spread among the two. Allowing the DRG to accumulate more damage than others and not remove hate from WAR. DRG with PLD on the other hand is a waste, because it's not needed.
The Ninja does more damage than paladin, but to be honest, Ninja damage isn't anything to write home about. They are good because they just don't take too much damage post 37. Pre 37 they are an akward tank, often requiring assistance from another melee. Remember though that damage translates into hate loss, so by blinking damage away, they can hold hate. With offensive ninjutsu, they can also build some hate too. They are often the tank of choice among more experienced, but they are extremely expensive to maintain properly.
The support roles can be looked at from the following jobs: WHM RDM BLM SMN BRD
But any 3 of them randomly chosen will not always work, especially depending on your choice of tank. I would say, for the most part, you want a RDM in there with a PLD. Refresh is a single target spell, and Ballad is not. Most PLD don't get Ballad during the actual fight and it makes holding hate a difficulty. It can certainly work, but, all things must be compensated accordingly. Maybe a THF in the PT at that point would be a good idea, even when usually it's a bad choice for PLD, as you need DDs capable of compensating thelr low damage capability. BRD and RDM work well together, but not with a WAR tank unfortunately. With PLD that means they get to be their own main healer, and have total control of mob. With Nin that's just fine becuase rdm can heal for nin as they get so little damage. War however require too much outside healing and need a WHM.
So... PLD want a RDM. WAR need a WHM.
Until level 25, you want two healers if you intend to chain effectively. WHM and WHM works, but if the RDM is good, WHM and RDM is actually better. The usefulness of RDM pre-level 41 when they can refresh is solely determined by the ability of a person to understand what that RDM is. What you are is... above all, a support healer to help continue the chain. You debuff, you dispell, all for the purpose of continuing the chain. Getting refresh is only the crowning glory on your job. But if you think your job is to whack the mob with your sword for 3 damage a pop, you are leading your job towards uselessness.
At level 25, WHM and BRD is preference. If RDM wants a spot they yet again, must understand their job. Once you hit 41 you go into the more standard combinations as described.
WHM RDM BLM is the standard. It's time tested. It works. Of course a SMN can replace either the BLM or WHM, but for main healing a WHM is preferable. As for replacing the BLM, it's about damage dealing. Do they have fenrir? Can their buffs translate to more damage than BLM's nuking. It's... iffy. At higher level, they are like DRGs are to DRK. High damage output without any hate. I think maybe WAR DRG DRG SMN WHM RDM works nicely... SMN can do intense damage and WAR will hold hate. At lower levels, SMN will be most usually main healer. Sometimes their aeriel armor is useful with pld tank, because the other tanks already can blink themselves. Stoneskin always great, especially for war tank, or the ocasional crazy ranger. However, don't replace BLM with SMN unless there's a DRK for stun or you know that stun won't be needed. If there's no blm, remember that unless someone has a 29+ BLM sub, no escape either.
As for the DDs. The party setup matters, but so does the zone you'll be fighting in. Are you gonna fight bones? Get a monk. Fighting flies, you would be well off with a THF. Some level up a secondary weapon to use for two purposes. Certain weapons are best on certain mobs, and certain weapons chain better with other weapons. Take the skillchain into account. Take a strong ending WS into account. Are you gonna fight crabs, can you do distortion? So often parties will form not taking this into account, and act once the exp is slow as if this was unpreventable. All these things have a huge bearing on your XP, so try to take them into account. It's handy for you to have an alternative weapon for exp pt as a DD, but... remember to have your standard present, as, well... you might have been invited with a certain skillchain in mind.
All this being said, maybe you can't find the right jobs to put together your perfect party. Is your party going to be at least decent? Are you wasting everyones time by assembling a piece of junk? Until an at least capable party is possible to assemble, go try something else. Fish, raise your cooking, level another job that's more needed at that moment. Please just don't force it. Don't make deadlines on your character's exp.