From what I've heard, I think that if FFXIV has problems with everyone being the same, it'll be in a way more similar to FFXI than FFX. That is, everyone of the same job will be identical, but outside of that there'll be plenty of variety. I imagine it'll take too much time to level multiple disciplines for everyone to have every skill, at least until many years into the game.
Of course, having everyone of the same job identical isn't a good thing either.
Well, but there are two things (not to **** on your rainy day).
1) SE has already said that it won't be quite as hard to get to "cap"
2) Accessibility. In XI, you were pretty locked in to your job at least for a particular event just because you couldn't go back and change easily.
But I guess while it might not be as hard as getting a Maat's Cap to cap all of your "jobs" it could still take quite a long time. Doesn't seem like much consolation though. So if they go this route, it will almost definitely be worse than XI, and probably treading pretty close to X.
But still. I hated the idea of that system in FFXI, and I still do in principle, but somehow it was still compelling enough to keep me playing for a **** of a long time.
I think that around the time of the release, there was still a lot of sense of wonder and exploration with the job/subjob system. A lot of players didn't really accept that there would be such stark differences in the different combinations to the point that they would be expected to have specific subs, and were even further caught off guard when they were expected to have -multiple- specific subs.
Obviously this developed from the contrast in balance between certain combinations over a period of time, but initially, people were excited about being able to be a WAR/smn, or a DRG/mnk, etc. I know many people did eventually quit because there were so many expectations to be a cookie-cutter, but the remaining playerbase eventually accepted it. Personally I always strove to be effective while remaining a bit unique.
Ok, now we're going to get slash fiction of Wint x Kachi somehere... rule 34 and all...
Never confuse your inference as the listener for an implication of the speaker.
Good games are subjective like good food is subjective. You're not going to seriously tell me that there's not a psychological basis for why pizza is great and lutefisk is revolting. The thing about subjectivity is that, as subjects go, humans actually have a great deal in common.