I've got a feeling it might not. I can see Sutherland progressing a lot faster as he's already adapted well to the pros. Or rather he didn't even need to adapt so he is in a far better position to move along the ranks. DeGale has many adjustments to make so he will be brought along slow by Frank Warren, who would probably not be as keen to chuck his charge in with Sutherland as Maloney would be. Only way this happens is if, and its a huge if, Sutherland wins a world title AND DeGale manages to jump through all the hoops and make it to title contention.
No matter what way these guys careers diverge I still see this fight happening. It's an easy sell. The scenario I envisage is like you said Sutherland climbing the ladder quickly, DeGale becoming another Audley, and using a potential Sutherland bout to rescue whats left of his career, the way Audley tried to do with Haye. I also think Sutherland would take the fight no matter what the situation.
Junior Witter vs Ricky Hatton.. And i think it may happened, only if Ricky Hatton looses to Pac Man..! But he will prob, just bully Pacman.