People are really underestimating the value of adding Horford.
This team was a top 5 defense last year with Amir as the only half-credible rim protector. We floated around the top 3 for most of the year. Adding Horford, who's a top-shelf defensive big and a real rim protector, to that mix is going to be huge. I think we could very well have the best defense in the NBA this season. That alone will make us a very good team
On top of that, one of our biggest weaknesses last year was that if you wanted to stop us, you'd just triple team IT every time he had the ball and wait for the shooting to dry up. Adding Horford changes that. If you triple team IT, Horford will take advantage. He can make shots inside and outside. He can be a featured player on offense. You won't be able to just throw the world at Isaiah anymore. On top of that, I expect to see Crowder continue to improve his overall offensive game, I expect Smart to do well in a bigger role, I think KO will be a key contributor, Bradley to continue improving his dribble drive game, Rozier makes a step forward, and Jaylen gives us a guy who can just get points when we need them.
Do we have weaknesses? Sure. Rebounding more than anything Else. Shooting is better but still needs to improve. But overall, this is a lot better team than last year, and I fully expect this team to hover around 52-56 wins. Don't sell Al Horford short.