I don't necessarily think the Hawks make the playoffs, but it's easy, for me at least, to see why someone would think they can, now that the rosters are complete. I'm just surprised by the 4th/5th prediction. I can see 6th-8th.
Yeah, they lost Johnson, but they also added several pieces that might mitigate the effect of the loss. Korver and Morrow can hit outside shots, so some balance is still there. Lou Williams and Devin Harris give them better backcourt bench depth over last year.
Also, Horford missed 50+ games last year. So his return is adding a substantial upgrade to their frontcourt over last season. And then there is the possible internal improvement of Jeff Teague.
5th seems high, but playoff berth seems reasonable. Not a sure thing but reasonable.