I think 55+ wins is realistic. We have proven established talent in PP, KG, and Rondo. We have a top 5 defense coming back. Losing Ray Allen doesn't hurt our defensive numbers, in fact replacing his minutes with Courtney Lee and Avery Bradley likely improves our defense per 48 at the 2 position.
At the 5, I think Stiemsma and Collins are a wash. Stiemsma produces more blocks, but Collins is more solid in one on one defense. Wilcox should be back and hopefully healthy as well. KG will get the bulk of minutes at the 5 and he is a plus defender in this league.
I really like the Celtics guard depth on paper. Rondo, Bradley, Jet, and Lee look like a very solid guard rotation. Throw in Dooling as a backup pg, we're pretty much set.
Bass + Sullinger make for a solid set of power forwards. The fact that Sully can rebound should help. I'm going to predict right now that the team we have after the trade DL will NOT be the same team we have on opening night. However the group of guys Ainge has gathered right now is still pretty solid and should compete very well.
Jet gives us a 'microwave' scorer as our 6th man off the bench as well as a 'handles' guy for the second unit. And Rondo is a beast PG. Nuff said.
The Celtics also got more athletic and younger on the wing by adding Lee to the mix. If Sullinger works out at PF they will have also upgraded their rebounding and big situation. Glad we kept Bass as he was a solid all-around player for us.