Defense is still terrible
Boston gave up about 108 pts per 100 possessions last season. Not very good but still 19th in the NBA.
The problem was more the offense than the defense but the real problem was a season-long habit of utterly collapsing after being competitive or even leading the other team. Some of that was youth, some injuries, some mismatched roster, some lack of talent, some coaching mistakes and some, I'm pretty sure, was by design. There's no way Sully keeps shooting 3s as poorly as he did last year unless Stevens specifically told him to.
Celts should have more talent this season (if nothing else, Smart will be a huge upgrade over Pressley, Thornton is probably going to be better than Bayless and we've added Zeller). If Vitor can stay healthy, having him, Zeller and Anthony to man the 5 should balance out the roster. Stevens should also be better acclimated to the league.
It all depends on Bradley's health, Rondo's interest in getting a big new contract and whether Wyc and Ainge really want to make the playoffs.
Mike