I agree that, especially when your team lacks talent, you draft for the best player available and try to make it work from there once you have a few really good players.
That said, all other things being equal, I think the best players for Stevens will be guys who can pass, fill multiple roles on offense, cover multiple positions on defense, and hit the outside shot at a reliable rate.
I think there are a number of players in this draft who fit that bill.
Aaron Gordon, Dante Exum, and Marcus Smart stand out in the 5-7 range where the Celtics are likely to pick.
Later in the first round -- Kyle Anderson seems like a possible fit, as well as Nick Stauskas.