I wouldn't trade either of those guys the way they are playing right now. Both are vital off the bench. Smart is Mr Toughness. He changes the team's character defensively. Rozier has been great lately off the bench.
What they can use is another big to help out Baynes, who has his limitations in terms of length matching up with other bigs. He couldn't handle Thompson the other night against Cleveland. He can body people inside, but he can't jump and has short arms.
Bogut is now available, but I don't know how much he can help at this point in his career. Chandler can be had for a lot less than mentioned (not Smart), but he's pricey in salary.