I'm just gonna go a different direction here and say Milwaukee. Go Bucks!
They finally sold the team to new owners who are major hedge fund players likely to do well for this franchise, most importantly by keeping them in town. Massive off season there alone.
Then you have the fortune to land Jabari Parker #2 and he actually really wants to play there. Huge!
I don't care much about Kidd ... jury out here. Minor to medium upgrade for most teams but kind of a big deal for Milwaukee.
A lot of young dudes who had poor seasons/injuries/issues last season coming back with a new attitude and a fresh slate. I'm looking at OJ Mayo, Henson, Eran, LARRY SANDERS?!, Wolters and others. They got Brandon Knight (was he once good?) and landed as couple other low cost vets and a 2nd round pick (johnny O).
All things considered, this is a franchise that has a whole new feel. I'd put them near the top 5 of best off season.