I actually would like this. We'd be lucky if MKG turns into half the player Rudy is. Why settle for something unknown when you can get the real deal (not to mention we'll have him in his prime). If we make this trade, get a post scorer, continue to develop Kemba, and see what type of coach Dunlap turns out to be after he gets more experience, we could be a dangerous team for 3-5 years.
I believe that we could acquire Rudy Gay without including MKG though. I would love to maximize MKG's offensive strengths by using him as a big SG that's difficult to defend in the post. It would cause a lot of matchup problems for opposing teams.
How not to become a playoff team: Build around the offensive weaknesses of a 19 year old rookie SF.