While I agree that the resistances in place in this game are generally a joke -- the only place where you have to put in any thought (or did) was BCoB T2, there's no compelling reason to put them in place. I think they've done a fantastic job of making every class/ job viable for every piece of content. Sure, there are a couple of pieces where job X might be a bit better than job Y, but nothing like the crap-fest in FFXI where many pieces of content could not be completed by the majority of the player base without at least a couple of slots being filled with specific jobs, if not the entire roster being set in stone.

Also, some of you guys must have played a different FFXI. The one I played, where I was a BLM more or less the entire time, had me casting blizzard spells 80% of the time. If I wasn't casting blizzard I was casting thunder.