I dont think they'd be cool enough to give us our own personal avatar, as mind blowing and awesome as that would be, its just not something SE would do in a game like this. Itd be a nightmare for them to balance every class for use with them, i mean its not like a summoner class thats specifically designed for pets. If they were only a '2 hour' sort of thing i feel like itd be an awful lot of development for something so limited but if i had to unleash my dreams, id love to have something like that. Perhaps choosing 1 avatar from a list, each with its own signature skill. I know if i could pull out Alexander for a 15 second invincible or Phoenix for Reraise, itd put me in the hospitals fangasm ward for a week!

I reckon the summoner job or something like it will come, it is an FF staple and many people have voiced their desire to see it. As to what shape or form its pets would be, thats anyones guess. I certainly dont think the materia system will have anything to do with them, it seems pretty self contained.