Because it is fun, how about this massive trade this summer
Trade happens after Durant indicates he is signing in Boston
OKC - Porzingis, Rozier, Olynyk, Calderon, Johnson, Jerekbo FOR Westbrook, Ibaka, Kanter
NY - Wesbrook, Kanter, Crowder FOR Porzingis, Lopez, Afflalo
BOS - Ibaka, Lopez, Afflalo FOR Crowder, Olynyk, Rozier, Johnson, Jerekbo
Various other pieces can be added as necessary. Essentially, OKC goes into full bore rebuilding by acquiring Porzingis, Olynyk, and Rozier for Westbrook, Kanter, and Ibaka (Calderson, AJ and JJ are salary fodder that OKC would presumably cut - Kanter's contract is a disaster on a team that is not a contender). NY gets a one year rental of Westbrook to give Anthony that 2nd star and gets a solid wing defender in Crowder and an upgrade at center (Kanter is better than Lopez), but does give up Porzingis, Afflalo, and Lopez to do it. BOS gets a starting PF and C to add to the new star in Durant, but does give up Olynyk and Crowder (though who with Durant and Ibaka become much more expendable).
Be an interesting trade for all three teams and again would be only after Durant says he is coming to Boston.
If that trade happens Boston would still have its 3 picks from 2016, one of which should be a guy that can help this year (let's just say Poeltl) and can then still re-sign Sullinger, Turner, and/or Zeller for roster depth (let's say Turner and Sullinger re-up). That would leave Boston as
PG - Thomas, Smart
SG - Bradley, Afflalo, Hunter
SF - Durant, Turner, Young
PF - Ibaka, Sullinger, Mickey
C - Lopez, Poeltl
The 2 extra spots would be the Dallas and Boston picks from 2016 which would be in the DLeague (the 2nd rounders are hopefully draft and stash players).
Clear title contender for a very long time with the right mix of offense and defense.