I personally am in the 'Trade Smart' camp to upgrade another position, but if you're rolling out IT-Bradley-Ingram with your choice of Kelly/Sully/Amir/Zeller at the other two positions, you're moving in the right direction.
Why not trade IT?
If we get a top 2 pick in this draft, the focus for our franchise becomes setting the team up to be really, really good right around the time Simmons or Ingram hits his prime.
By that time, IT will be on the verge of being a 2nd or 3rd stringer, if not out of the league altogether. The history of guys IT's size, whose game is predicated on speed and scoring, is not good beyond age 31 or so.
IT would probably fetch a better price than Smart anyhow, and Smart is more likely to work well alongside a ball-dominant star or high usage scorer.