I don't know why folks here are so eager to ship Fox off. At least another season of the 3 guard monster will keep the Spurs as a championship contender... Help Dylan hone his off ball chops even more and most importantly let the Spurs be the OKC nemesis.
The Spurs shouldn't put the cart before the horse. As for KD, there is no need to bring in a 37 year cantankerous All Star who quit on all of his teams ever since he was rightly called for bandwagoning onto the Warriors.
The Spurs should try to improve on the margins next season. Get a very good back up to Wemby and Kornet. (How about Porzingis being given a chance to resurrect his career or Timelord?). Get a better shooter than Lindy Waters (will CJ McCollum come over chasing a ring? How about Matisse Thybulle). Load up on more 3 and Ds to replace a flagging Barnes. (Tobias Harris on a cheap?).
There is no need for any big bang for at least one more season.