If you leave DT and TD open, they will almost always pass up an open shot. They do not make the opposition pay by hitting shots every time they are open. If you re-watch the games, they pass up a LOT of open shots, and only shoot 3's when the shot clock forces them to, or they hit lay-ups or put-backs.
Again, they don't take enough shots for their efficiency to be a significant contribution to the offense. I agree that MW is not a great defender, but overall our defense this year, especially defending the 3 point line, has been dismal. We might as well start MW or play him for starters minutes and see how much he contributes to our offense.
EDIT: I have recorded every UR game that has been televised on DirecTV, and have re-watched a number of them (don't ask me why, sucker for punishment). TD and DT do not make the other teams pay for leaving them open, they simply pass up a TON of open shots that a decent-shooting D1 basketball player should take.