Dudley, like Lee, is an excellent '3 and D' guy. Dudley is also two inches taller than Lee. Calling Lee "vastly superior" on defense is nuts. I've watched Dudley play, and he's a darn-good defender.
Factor in that Dudley is on a better contract than Lee, and Dudley is the better player.
Having a size advantage doesn't automatically equate to having a defensive advantage. Considering your own team carries a prime example in Avery Bradley, you should be well aware of that. Again, both statistics and a good old-fashioned eye test can confirm that Lee IS indeed a vastly superior defensive player. It really isn't close.
Otherwise, as hpantazo pointed out with basketball IQ and 3-point shooting, and as you pointed out with the better contract, I do agree with you all that Dudley is the better player.