If Smart were BPA, then I assume Utah would move Hayward to SF or even work a sign-and-trade. I doubt that happens, though. Unless the Jazz land in the top-3, which I believe is clearly defined, BPA is going to be subjective and team needs may play a part or as a tie-breaker.
1. Wiggins
2. Embiid
3. Parker
4. Gordon
5. Smart/Exum
I don't really know enough about Exum to rank him above or below Smart. I'd draft Smart and play him at SG. Definitely wouldn't trade Gordon just because I got Smart. As long as Gordon isn't signed to a ridiculous contract, he will be a trade-able player if need be.