Kerr was an inch or two taller but I would bet anything that Jimmer's verticle is way higher.  At least Jimmer could dunk, and rumor is Kerr couldn't (not that it matters since shooting doesn't usually require a good verticle and may become a problem as legs get tired-I've always heard the best long distance shooters only use a 2 inch verticle when shooting0.  And I would put money on Jimmer's movement speed over Kerr.  This is what frustrates me about the NBA.  The Bulls and S.A. showed a great forumla for how to become the dominant team in the NBA but nobody seems to follow that formula as though its not possible to put together.  Too bad because Jimmer would be an all star if they did because he would be knocking down shots from 3 off of passes with dribble penetration just like when Jordan  and others would penetrate a defense and kick it out to Kerr.

As for defense, just do what the Bulls did, one especially tough defender (Jordan) that made the other players better because he would force his man to make a bad pass leading to a steal by Pippin or Kerr and then a pass back to Jordan for slam.  Every team in the NBA practices defense but the key to the Bull's defense was Rodman and Cartwright.  They cleaned up the board so most teams didn't get second or third shots (especially with Rodman).  No matter what you do in basketball, most players will somehow get off a shot and if you don't get the missed shot then the guy that gets it will have a two to three foot shot with nobody ready to defend that shot.  The Bulls and SA knew this and that is why they were so dominant on defense.  Limit the number of shots by the other team.

And finally, Jimmer is lights out at the line.  You pass him the ball he can handle it, take the foul, and make the shots.  Game over.