He has a community post on youtube about that.
Recent community posts
I don't remember if I said this already, but I think an ADS that slows time a bit in the air or on walls (gradually consuming the time gauge) would be super cool and make kills while doing parkour a lot easier.
Steven, I think that all the "people" (character, enemies) being energy-based lifeforms would be cool. For example, what if there were rails that you could ride by turning into an electrical current: and maybe "ammo pickups" could just be energy you're siphoning from the enemies would be cool.