Well I'm not going to quote any of the others because this page is long enough, lol.
Kisada's right in that a well equipped WAR and even most decent equipped ones can out parse a majority of the other melee except for MNK and NIN. Those three really are the kings and we all see that. Generating more damage will add to your ability to hold hate, but there are more things that make a good tank.
For that reason WAR are not the better tank than NIN. The NIN has his enfeebles for hate, almost the same dmg output for hate, some arhat's if he needs enmity, still has his provoke/warcry plus he'll dodge more and have that one extra shadow. I would agree that evasion gear is mostly a moot point on merit mobs because they don't last very long, but saying evasion doesn't matter is wrong. If you max out your utsu timers then the mobs will get through and that time you spend with shadows down is MP used by your mages.
A NIN w/o gear has 269 evasion (possibly merited to 277) while the warrior has 225 and most likely not boosted, actually probably reduced due to hauby/hauberk, atk earrings, etc. So a ninja in a DD setup will still have more evasion than a WAR in evasion gear, that can make a profound difference. The ninja will still tank well while keeping on his DD setup. I mean Ninja hit 225 evasion at lvl 66, 9 levels sooner, it's not a small evasion gap.
Every attack dodged/parried/absorbed is MP not spent. Even if he dodges only 2-3 attacks a fight that is 2-3 shadows not used, or 2-3 heals not used and will stack up over time helping to keep the party going, or to keep your 1 RDM healer happy. And it comes to the NIN naturally, he's not really sacrificing any dmg (other than casting time) to do it.
Notice I never mentioned that WARs can't tank, I've used them in merit parties too. I've even been main tank once (mainly because the real tank wasn't that great) as SAM/NIN. But it doesn't mean that WAR nor lolSAM is the best tank. You'd be hard pressed I think to convince people that a WAR will be the better tank unless your goal is merely to keep swapping hate around amongst your party, but even then that means you're counting on someone to out DD you.
*phew* Now that I put my spin on that issue, I'm curious as to what others think could be solutions to 2H weapon damage. Personally after doing some more sky farming and dynamis this week, plus a merit party on Sunday I'm getting continually frustrated with doing nearly the same dmg in 1 GKT hit as my MNK friend does with 1 fist. Breaking from the game from a second, how does a sword that can sever your arm do less damage than one punch to the gut?
Ok, back to the game mechanics. One axe or fist strike has, on paper, lower weapon dmg and a comparable skill cap. STR is also fairly similar between SAM and other DD jobs and isn't as much of a factor on regular melee hits. So my guess is that it's the attack bonus that makes them hit almost as hard with one hand what it takes me two to do. So one simple solution could be to give 2H DDs some kind of attack boost when they have a 2H weapon equipped, but there must be some sleeker way of tweaking the system. I'm interrested in hearing what others have in the way of ideas.