I don't know how easy it would be to add to C2, but layer time scales would make life so much easier. You could do a whole bunch of slow motion and camera tricks very easily. With object time scale it's just too messy for a lot of things and adjusting the entire time scale messes up your timing.
But even if it doesn't get included, has anyone found any nice clean solutions for this sort of thing? Say a character layer moving at 0.5, background at 2, effects at 1.5 and UI at 1? (and turning them all back and forth regularly depending on conditions)