I think Rondo makes Bradley, Green and Jordan better players.
That said, Rondo for MKG and the #4 pick doesn't sound so bad. McLemore might be worth the gamble.
One thing to remember, Rondo always got by without a jump shot because he was so much more athletic than everyone else. Will that advantage be gone if he loses even a half step? Think of how many small guards became shells of themselves after leg injuries. Penny Hardaway, Tim Hardaway, Marbury, Steve Francis, Michael Jordan. Ok, well maybe not the last guy, but you get my point.
This might be the best time to trade him, before people realize he's not the same player.