What I'm thinking is they will stick to basic classes such as your basic marine, raptor, devastator and sorc. But from there be able to specialize via god or some sort of perks/skills (sort of basic mmo styled). Ie a Devastator could become a noise marine by aligning with slaneesh or something. Also Terminator armour would be pretty badass.
Noise marines and Lords of Slaanesh on steeds! Also swarms and swarms of plague zombies under Typhus. Also I need my Daemons. Ok WTH I want CHAOSSSSS
As much as I'd love a sort of twisted Apothecary class I also don't want CSM to just be "Space Marines with Spikey Bits" My prediction: Chosen Havoc Raptor Sorcerer
I don't like the class system but it isn't bad either ... But one thing ... PLEASE ... I DONT WANT ANOTHER TANK, HEAL, DD MMORPG. It would be nice if you manage to combine elements of these systems. But in the current Warhammer 40k ... there are three things I would like to be. Nurgle Warlock. Grey Knight Purifier Seneschall, Salamanders Psyker(burn baby)