yes, corruption (with a new name) will be a keyfeature in the strategy of the tauri and will be used for tactical missions that tell the story.
the yellow fog will be replaced. (apparently by a light bluish glow, but that may still change)
standart eaw/foc events will be removed.
in the German board, however, they suggested rioting planets you have to defend in tactical missions after reaching a certain state in the GC (which would not necessarily be random and has not (yet) been approved by the MG)
apart from that i don't remember anything else being mentioned yet