Tire III should only be casted when the convert clock is ready, or ready enough, Rest does not give RDM enough MP to last when tire III is used more than once in the given 10 minutes. At the most a RDM can use Tire III no more than twice before convert. Blizzard III for instance costs 120MP if there is a Skillchain and a BLM there is no reason for a RDM to blow away 120 MP when the mob is just about dead, or even for one attack for that matter.... Remember a RDM with MP is one that can function. Tire III with rest will not ensure stability from a RDM. Only when the clock is at 0 or close enough should it ever be casted, i don't know if you'll ever know this. Tire II is good enough and will not make for overkill.
- Anttaru
I always Magic Bursted with my highest Tier Spell, yes even Tier III. I did my job, kept a refresh cycle up, hasted appropriately, enfeebled, etc. Everything a party wants from a Red Mage. Helped heal. Never did I have MP issues for it.
Obviously, you DO NOT Magic Burst with Tier III spells if its going to be overkilll. That makes sense. But that is the only time I can think of not doing it. Just like you shouldn't melee if the mob uses a very nasty AoE. It's just something you have to sit back and think 'Duh!'. Not a reason to never use it, just a particular instance not to.
That being said, I don't know how or why you can reason that MP is the issue, particularly in the later levels. I'm a Mithra, now 75 RDM for a while, but even as I was leveling up I never had MP issues by Magic Bursting with Tier III stuff. My gear was average at best. I never had any complaints about my job. If people question my words, ask around, maybe I am wrong and someone finds me to be a totally inept player but were too afraid to tell me. However, I did find a lot of praise in people glad I was doing the job of a RDM. I religiously Magic Bursted (and to be honest, was complimented a lot that I did so while still maintaining my duties as RDM effectively) with my best spell available when it was applicable and not a waste of MP. I am not a taru, just a Mithra, so it isn't like I have extraordinary MP to work with either.
I guess my problem is understanding where MP is an issue in this argument. You can toss examples of when it might be a problem, some instances, but to be quite honest and blunt, I think people who argue against Magic Bursting Tier III spells are just not adjusting their partying tactics for it. I'll admit, as soon as I got my first Tier III spells that I regularly used, I relied more on my Convert timer. However, every level that passes makes that less and less necessary, while still Magic Bursting with Tier III spells.
Another instance to not MB with highest tier spells: If you're main healing. I know there are times it isn't appropriate. But that doesn't justify it not to be done when playing a purely RDM role.
I'm not trying to argue RDM Melee is pointless. I have yet to see a really effective RDM Melee in a party setting, as they usually end up slacking in one area or another (but they themselves usualy think they aren't), but I know it probably can be done. Perhaps you can do it. Perhaps the next up and coming RDM sitting in Jeuno LFP can do it. I just found something wrong when people make claims how doing something like bursting Tier III spells is not effective or doable, when I myself did it throughout my levels as RDM. I have yet to see how it wasn't beneficial, nor that it was an impossible task to accomplish. *shrugs*