Here's a list of things that were relevant to me at one arbitrary point of my time playing ffxi.

-sky
-sea
-limbus
-dynamis
-salvage
-nyzul
-znm
-big 3
-einherjar
-many other world nms
-storyline
-campaign

that's 12 things having to do with nm raiding in a group, these things were all useful to me simultaneously and continuously having 3~6 classes just because I already have a body armor doesn't mean I wouldn't do better lullabys in another body armor or be a better tank in a certain set up etc. Idk if you can but I cannot think of another mmo with more than 10 different type of raid oriented loot seeking events continuously in use for such a period and I have played a bit.