It looks great. I don't know about the switch anytime for any mission protagonist setup for gameplay purposes but it looks fun for story purposes.
I just have a feeling that it's going to be overscripted like IV was. Like with car chases, where it's impossible to catch a guy until you get to the correct scripted point. If I outsmart the AI or just get a lucky gunshot on a tire I want the car chase to be over in seconds.