As much as I harp on TJD for not being able to shoot after four years in college I was very impressed with him this year. He has become an excellent player. I just don't see how he's a better fit than Zach for this Purdue team. I get the argument on defense and I mostly agree, although it's hard to measure the impact that Zach has by dissuading opponents from coming in the lane. TJD is an excellent shot blocker but I've watched a fair amount of IU basketball and I haven't seen opponents completely abandon attacking the rim the way that I have with Zach.
Offensively TJD just doesn't dominate or draw attention in the same way that Zach does. Now Zach's supporting cast needs to take advantage of that by hitting open shots but overall Zach won more games last year with a worse supporting cast than TJD.