FFG likes to have each faction sorta focus on one thing. What would that one thing be these guys?
Obliviously this is just guess work and has no meaning.. no one knows but the NDA beta testers.. still I think it would be interesting to see what others are thinking. Plus we get to talk about the game.
I think IG would be a rush race... and I kind of think if they were knights would it would be really cool. a knight is a type of card that buffs other cards sharing the same keywords. So say you have a 0 attack IG trooper, that adds +1 Attack to all IG Troopers... so 1 might is 1 attack (0+1buff) but 2 out would be 4 attack (0+2buffs each card). This would be good for IG as they focus on mass units in the tabletop supported by heavy artillery. I think this would make a good "focus" for IG.
Orks could also be a good rush deck but I think the cards would be stronger on there own as orks are pretty tough. So I would say strong cards with resource ramping to make them play cheaper.
Chaos... with all that demon summoning.. I think maybe bouncing cards.. things that come into play then bounce back to hand or sac at the end of the turn. Like you summon a bloodletter and it has to remove a counter each turn, when no counters it dies.