*crickets* Um... okay
I haven't tried Ifrit on PLD yet, but on "something similar" yes I do believe I have. As for GLA, I've had my MP get exhausted before - easy enough to have a THM come by and SP > SR on me just before stops dashing around so as to get hit with a high damaging breath attack to provide the most MP back during SR's duration. So far, for both, running out of MP on either PLD or GLA have been very situation - both of which can be corrected (or made worse) by altering strategies.
How is this different than having it be required that GLA have Featherfoot and/or Sanguine Rite just to keep his/her MP up? The only difference I see in that is by not having those abilities you have to rely more on another party member to provide the support for you.
Hmm, good thing "long, drawn out fights" require party members to help win. *Solution found.*
BRDs don't need to ignore anyone in the party, especially with regards to putting up songs. Just like a THM can find the right moment to put up SR on the GLA in an Ifrit fight, so too can a BRD find the right opportunity to put up a 3 min (or is it more than 3min?) song on one party member (or a select group of party members), and then go back and put up a song for the 'other' party member(s). And, if "need[ing] to run around to get everyone songs" (which, you know, is what BRDs do) is clunky, then I guess fighting Ifrit is just as clunky because it requires you to, you know, run around and avoid ground mechanics.
I actually like it when ppl bring up FFXI. Most seem to think that there's not "Final Fantasy" in FFXIV, and that it's awakens the anti-christ for mentioning a previous installment of a FF game when, you know, talking about a current/new FF game (because FF games never have anything similar/familiar in them... never). Anyway, I digressed...
You're absolutely right about having multiple ways PLDs could replenish MP in XI (pre-abbyssea, or h/e it's spelled. I say that because I stopped during WotG). But, even with having all that MP available to use you still could hold a lot of threat by relying on other members of your party for threat: THF, or anyone that /THF. That alone I would argue could give PLDs in XI the majority of their threat; however, it just all depended on the pt setup and situation.
Yeah... Hmmm, games like DCUO, WoW, Rift, etc., where every class had their own way to be self-sufficient, I find really hard to try and compare to FF games only because historically FF games have centered around strategic, tactical battles that involved micro-managing party members to perform key roles in order to win the battle. And I'm not suggesting that the battles in those games didn't involve any sort of strategy, it's just they were completely different (again, imo) then the strategies used to win fights in, say, FFIV and FFT, etc. Anyone, the thick of it is, every MMO will have their own class-structure to it, and to say stuff like, "I played this one game, and so this other game should have it simply by virtue of the other game having it" is purely subjective.
All in all bro, FFXIV allows you to play GLA or PLD whenever you want, and it sounds like you already have your mind set on GLA. Whatever you do, hope you have fun doing it because after all it's a video game, and we all choose to play it based on what it offers us. XD