Hm, these are all interesting. Some comments:

Everyone who can play 2 roles will be dual-spec - druid will be Feral/Boomkin, Priest Disc/Shadow, and the shammies will all have ele/resto specs in case I need to cheese some fights by simply soaking up gimmicks and healing through them. I also like the idea that I can dispel pretty much anything with that team. And yeah, Jack - Wind Shear is amazing and extremely useful, a round-robin for using that was the second thing I set up!

I'm not sure about a warlock - I don't really "get" them, but I would like to be able to field any class eventually. With a DK, I did originally start with 5x paladins, back in Wrath, so I don't mind doing melee, though it gets a bit more complicated in some ways I guess.

Mostly this will be a PvE team, but I might do some PvP, though with PvP I really like to run 5 of the same class just for amusement's sake, so that would probably be a different team.

Thanks for the ideas - I hope to start putting them into practice once I manage to level some groups up!