I disagree. If they're serious about putting up a title contender, then they need to blow it up and start over. This team won 60 games last year, which is legitimately the ceiling for them. Where did that get them last year - a sweep at the hands of the same Cavs team that swept them easily this year. I don't think Milsap and Horford are good enough to be the backbone of this team as a title contender, and adding someone like Howard or Whiteside would only replace one side of what they'd lose out on with Horford. I don't think you can play Milsap, Horford, and Howard/Whiteside together full-time, especially with all of them getting older.
I'd let Horford walk and shop Milsap and Teague for the highest bidder. There are two teams in New York that'd overpay for a point guard right now, especially if both of them miss out on free agents. Milsap would also bring a good haul back to Atlanta. You could get a couple of good prospects and some extra picks to help you build around Schroeder and Hardaway.
This is also the perfect time to blow it up and tank for several reasons - 1) the 2017 draft is supposedly absolutely loaded, and 2) most of the tanking teams (Philly, LAL,Brooklyn, Phoenix, Minnesota, etc.) look to be on the upswing, have no incentive for tanking, or in Philly's case have finally decided to start trying to win after tanking for three years. If they blew it up properly, they could easily secure the best odds in the loaded 2017 draft.