Ellis and green both have valid points.
Yes, by all means trade any asset not named Hayward, Gobert, Favors or Exum to get a 5th stud starter. You only need a rotation of 8-9. We have that.
1. Priority #1 is to upgrade your starters if possible. I think DL will try that. He won't trade Exum, but he could bring in someone else who is ready right now to make the starting unit better. Exum then develops as a backup - or maybe even starts but plays backup minutes. Kind of like they are doing right now. Trey is averaging about 30 mins and Exum 24. In that scenario, it would be replacing Trey with someone who shoots better and shares the ball. I hate watching Trey who thinks he's the best ISO player in the league. And puts up shots with 6 seconds remaining when they're trying to get the last shot. SHARE the DAMN BALL! The other option is to bump Alec to a 6th man role. He would be fantastic, IMO. But again, not with Trey on the team.
2. Upgrade the bench. Need another big even IF Booker remains. Ingles, Hood and Millsap are decent, but could use an established player, especially of the "3&D" variety in case Hood ISN'T the answer or continues to have injury problems. Ingles and Millsap become deep subs.