LOL, killing faster dose not reduce damage taken over time , it simply reduces damage taken due to the fact that the fight is taking less time all together. And I would have to question , seriously, WHMs being able to nuke more offten due to this set up. IF you are taking more damage then another tank, there is a good chance that you are needing more cures more often wich would NOT free up your WHMs to nuke, and if the duration of the fight is inherintly faster due to the party set up it only feeds to the argument that the whms would not have enough time in the fight to contribute to the DPS.
Even tho its great that you get the speed kills and all, I think that is what is broken about the system. Players are reward greater on knowing how to exploit a broken game vs being actually skilled at their jobs. Before anyone gose off on a tangent let me explain...
The party set up described above dose take considerable skill from the tank to mesh vokes and other hate abilities with surviving a fast pace battle, however, I can not say the same for the blm/s or dds in this set up. The only skill involved in the DPS portion is simply knowing wich combos do the most damage and how to speed cycle through the spells. Personally , anyone who solos thm to 50 or blm , would already know these things. As far as the healer/s go, well kinda simple I would think, cast cures non stop to keep the tank alive and x fingers you dont drag hate. combined with well timed buffs and there shouldnt be much more to healing in the proposed set up. All in all a fairly low need for skill involved, having gear that is geared twards this type of party only increases its effectivness, of course.
Now lets look at what is ,imo, a system that requires skill on all parts. I will call this hypothetical boss, XX, as it dose not exist in the game sense there (enless extream ifrit is xx) is no boss that can currently truly challange skilled fight. when fighting XX, the tank can no longer count on the healers to keep him in fresh supply of hp at all times. He must instead , and quite often dose, use most if not all of his/her mp sustane him/her self. The tank must also know, to a fair degree, the ins and outs of his/her job and how best to sustain hate, reduce damage and generate mp/hp when possable. This would also call for the DDs to know what abilities to spam in order to reduce magic use or generate TP, knowing when to use abilities/spells (timing moves and positioning correctly) doing all this and staying out of dangerously low hp numbers at to not add un due stress the healers. The healers, after all, are already doing all they can to keep buffs up , conserve mp ,and reduce enmity drag. Again, this set up is not nessicary simply because there is not fight that exists that would push the skill level of every aspect of the party. And having gear that supports this party set up ,IE dps gear for the dds and enmity- where possable, mp,mind,vit and enmity- for the healer and def/vit/mind/hp/enmity+ for the tank, would only increase the effectivness of this party set up.
Again, all this is my opnion, but then again, some people would put know how to avoid damage , in the "skill department" I agree it dose take practiced tatics and a working knowledge of the fight to avoid attacks from a boss, I certainly dont agree that avoiding attacks necissarly test the skill of the player for that particular job. But if it works for you, go with it, however in its current state, I have yet to see a fight that challanges the skill level of the entire party, All fights tend to lean on one aspect while going OP on everything else to attain speed kills.