Some people think that Thompson isn't going to be a good center, and some think that Varejao should be traded. I disagree on both counts, and that's in part because I think they'll work very well together.
On offense, Varejao's best move is being the pick in the pick-and-roll (or pick and pop, or whatever). He has a good 15 foot shot, and isn't all that tall or athletic. When he works with Kyrie, he will set the pick, and then either head for the hoop or take a pass and shoot it. This keeps him from wrestling inside too much.
In contrast, Tristan's not going to hit anything outside the paint. His job will be to stay just outside the paint. If he's left open, there'll be a quick pass and a slam. If he's not left open, his job is to gather offensive rebounds and put 'em back in or pass them back out. He certainly will have the physical tools for it, if he bulks up (and I can guarantee he will). The problem for him will be mental- when to pass it back out instead of shooting it. He hasn't had a real pre-season yet, and he's not being used properly this year, but I have faith in him. It's not rocket science, after all- Varejao's job requires more mental work. Luckily, Varejao has a very high basketball IQ.On defense, their jobs are very similar. Once again, Varejao is the elbow-out guy, who guards big guys who are well outside the paint, and occasionally doubles the man with the ball. He's shown he can do this very well. It takes a lot of energy, but it isn't as physical as 'bumping uglies'.
In contrast, Tristan needs to work the inside. Against some teams, he does very well at this. Against others, he gets pushed around too much. He's also getting those damn 3 second lane technicals, which I believe is mostly caused by him getting pushed. I think he's strong for his weight already, and will be able to hold his own inside once he gains weight. At that point, his athleticism will get him steals, blocks, and rebounds.
Having an elbow-in guy like Tristan combined with an elbow-out guy like Varejao should work well together. Each one has a weakness that's the other guy's strength. Varejao can roam while Tristan stays home. Together, I think they'll work even better than each one did individually. Kyrie and Varejao can play the two-man game, while Tristan's good enough on offense that opponents can't cheat off him. All we need to add to it is a wing or two who can reliably score when their man cheats and tries to help out against Kyrie and Varejao. Luckily, we have lots of cap space and a nice pick or three in the draft. Getting that wing should be very doable this summer.