@OP: You forget that in FFXI (specially in the case of CoP) you had zones that were designed for the story rather than the story designed around the zones. Most of those zones were too far out of the way to be of any real use to players at large.

In the case of Al'taieu and Tu'Lia, sure you had bosses that you could pop and fight the bosses out of order, but it wasn't that different than running a raid. You're putting too much value on being able to fight the bosses out of order and devaluing the fact that because instances are designed with the bosses in mind, the fights tend to be much more mechanically involved.

I'm not against having zones connected to endgame, but I am more in favor of world-relevant zones over story-relevant zones. This is not mentioning that with quests being one of the main ways to level in 2.0, you technically do get zones that are unlocked as you advance the story. This should not stop the devs from introducing well-designed and memorable zones, though.