Unless he's permanently lost a step or the price is very high, I'd go after Favors in a heartbeat. He's been a steady 16/8 with excellent defense for years, he's only 25, and he's under contract for another year at $12M. We also need rebounding and rim protection. You're upgrading the 4 spot at both ends of the floor, and letting Amir play more against backups. You can play KO or Jerebko more when the matchup dictates.
Suppose we can get him for Zeller, Rozier and a future 1st.
Suppose we win the staring contest for Butler and get him for Bradley, Zizic?, BKN 18.
IT / Butler / Crowder / Favors / Horford
Smart / Brown / Jerebko / Amir / KO
That's a hell of a flexible 10 man rotation with a lot of good defenders on top of improved offense. Especially if Love is out long enough to get us home court, we're a serious contender.