The only time it matters is if your going to be pugging high mythic+ keys, then you probably want something meta so you can get more invites
Currently that is probably veng dh, prot pally- disc priest, mistweaver- some combination of mage, shaman, destro, bm hunter, aug, balance. So not a bad idea to have one of those available if thats you goal
And then all that can change with one balancing patch