Ainge has a lot of work to do to build a solid bench where everyone on it can play but I don't think this team needs to be blown up. We need some tweaks and some good vets off the bench but our top two of Tatum and Brown are stars which should be the hardest part of team building. This year was a disaster in so many ways but next year could be as light as this year was dark!
We can definitely build around Tatum and Brown, they're just entering the prime of their careers. Timelord as well though we need insurance for him given his injury history. Kemba we can shop to see what return we get for him. There's only so many points for a No3 if JT and JB are scoring 25+ each but Kemba's efficiency has gone down from his Charlotte days. I feel like the lower usage he has in Boston has something to do with it, he's a rhythm player and I think if he doesn't get enough touches he starts to lose his rhythm. But I doubt we will be able to move him without ending up giving away a lot. I honestly can't think of a team who would be willing to take Kemba at a reasonable price.
Smartacus we should also shop but he's a good 4th/5th option, when he can focus on defense and shooting open 3s off the catch rather than having to feel like he's the No2 option (which he was in these playoffs). I would like to see Fournier back depending on the cost, we do have his Bird rights but we have to be careful we don't get hard capped. Nesmith, Langford, Pritchard, they showed enough that I think they could be persevered with, though they probably need a bit more seasoning instead of being thrown into major roles like they were this season. That's really been our problem this season, injuries and absences forcing players to fill roles a pay grade higher than that they otherwise would have filled (e.g. Smart becoming a 2nd/3rd option, Gwill or the Green Kornet being the first big off the bench, Semi being in the top 8, etc). They just haven't been able to meet the elevated standards expected of them in those roles, but they would be fine in lesser ones.
I think everyone else is fair game. As for management and coaching, I don't think Danny and Brad are going anywhere, no matter what people wish.