The first thing that came to mind on your idea, was the last ZM fight when you break the exo-plates then fight the main boss. It seems like a semi fun idea if done right. I think you have an interesting suggestion.
I was on Wow wiki and I read up on a fight that involves dismantling multiple parts of the fight over a course of time and I loved it. WoW will definitely be my new home until the next gen MMO comes out, because regardless of its problems, the events and abilities implemented into the system feels far "newer" than FFXI. FFXI characters feel stiff if they aren't friggin NPCs, who get all the nice moves, but only in cutscenes (think ToAU CSes -- brilliant, but where is OUR ability to move like that?). In WoW, its the other way around, with the PLAYER feeling fluids and the NPCs feeling stiffer, which I love.
FFXI is old in the sense that they refuse to become new. That's the only real reason behind it -- the game has had plenty of opportunities to steamline itself into something that resembles the newer age of MMOs -- players with plenty of motions and choices, players with voices and the ability to jump, swim, and interact with the scenery around them -- FUCKING FOOD THAT YOU CAN AT THE VERY LEAST SEE YOURSELF EATING/DRINKING -- the list goes on and on.
It took SE over 4 years to introduce a broken windowed mode; that basically sums up everything. Anything you could ever want for the game will take 4 years or more to be implemented. I'd been begging for a 2-handed adjustment ever since I saw the disparity between damage at level 30, 4 years ago; I received it this past August -- that's sad.
Once I saw how pathetic the expansion was, when I had such amazingly high hopes for it (Hydra Corps anyone? They were the first group in this game I actually felt a sense of tragedy for, and they're still not in the expansion -- not even a fucking hint!), but again, the lack of content and lack of informing the playerbase what is in store for the future -- its the same old thing, and apparently more and more people are starting to agree, abet begrudgingly.
My revolution continues! Someday I will build my own MMO, and it will be neither "easybutton" nor "omg 3% droprate on everything good!".