This feels like a very, "what have you done for me lately" skewed sort of poll.
Boldy happens to be having a fantastic season, and Cozens has had a bit of a slump this year. But they're both very young players. I still take the big, fast ~70pt Center with two-way upside that has yet to be really honed...over even the hovering just under ~PPG Winger.
But obviously Boldy is having the better season currently, so that's the obvious "safe" choice. Rather than betting on Cozens bouncing back and continuing to grow from there. I think you also have to really factor in how much of a mess Buffalo has been. This sort of thing seems to infect their promising young players. He's hardly the only guy having a "down year" in Buffalo right now. I think he's still going to be a really darn good player when he comes out the other end of this. And at the much more valuable position.
Not that you can really go wrong with Boldy at this point. I just stick by a longer view of things, rather than just the guy having the better current season.