I think Marshal's bet on a Chaos Sorcerer is a good one, though - we still haven't resolved that Rumor Mill pic with the dragon-face that's identical to sorcerer backpacks.
I wouldn't bet on everyone getting Endless Spells, though. I feel like we're more likely to see a kind of divide between Psyker and Anti-Psyker, with the former getting Endless Spells and the latter getting something else.