You just solidify my point with each of the players listed above. None of the above players were dramatically better by the time they made it to their last season with the Gophers. In each case you see a player that ends up losing confidence by the end. I will concede this: At least Damian Johnson didn't get worse.
As for Paul Carter (left early), Al Nolen (academic ineligible and broken down), Blake Hoffarber (half the player he was by the end of his career), Abu Shamala (better his Jr. season than his Senior year).
There is not one player that has dramatically improved their basketball skills and become a phenomenal player under Tubby's tutelage. In fact, on offense, we see regression in many players that Tubby has coached. I'm not a big fan of Tubby on the offensive end of the court. He's proven to be a really poor coach in the half-court. He relies on defense creating transition points, but he couldn't design a play to get himself out of a wet paper bag if it requires running it out of a half-court set.