I like yoshi-p's idea, I think it's original and makes sense. However, I still think that summoners SHOULD still have their own avatars (the more the merrier) aside from the big guys.

Now about the primal summoning system, I really really really really REALLY hope that they can't be camped. And there should be many things to avoid this:
1) Each primal spawns in 10+ locations and changes his location every couple of hours.
2) The location in which a primal spawns should require parties of 4+ to enter. (dungeons, etc.. Otherwise free companies will split their members to the primal spawning spots and camp)
3) Free companies can't acquire more than one primal at any one time, and there's a timer after the primal is summoned.

I don't think "finding" the primals should require talent/ team work/ cooperation, because after a couple of months people will figure out a way to easy mode their way to a certain primal and acquire it repeatedly. But of course fighting against them to be able to summon them should require all of them (talent/ team work/ cooperation between the free company members).

When you come across a primal it should be like "OMFG IFRIT IS HERE!!", rather than "Hey I'll go find ifrit whose coming? :/"

Yoshi-p please please please please please please please do not make camping primals possible...