Two stinkers by Vassell doesn't take away the fact that he is the only two-way player in this team with a net positive plus-minus on both defensive and offensive end apart from Wemby. Vassell still needs to find a way to score inside more and keep the three-ball option a strong one instead of relying on jumpers all the time. That is the only boulder he needs to move in order to establish himself as a potential All-Star player in the near future. I am confident he can do it considering he has really outgrown the scouting report when he was drafted at least on the offensive end. On the defensive end, he shows flashes of the smart help defender that he promised to become, but still needs a bit more consistency on the one-on-one end.
Keldon will be a great sixth man in a contending team. Book it. He would make a of a difference in a Warriors team in fact teaming up with Paul, Podziemski, Payton and Saric, for e.g. backing up Curry, Thompson, Kuminga and Green. Or the Lakers or the Sixers where they can afford to deal with his lapses on defense but where his energy would be vital as the X-factor. Too sad, he is asked to be among the leaders here among the rebuilding Spurs.
If the Spurs get lucky in accelerating their timeline and getting a free agent like say, Paul George next year, then Vassell and Johnson will be great in their respective roles behind Wemby and George. A PG is key too, but the Spurs needn't look for a superstar. A Malcolm Brogdon or a Tyus Jones would be good enough to round out such a squad. Imagine this (a pipe dream, but still) --
Brogdon, Jones, Wesley
Vassell, Moses Moody, Cissoko
George, Keldon, Champagnie
Sochan, Risacher, Mamu
Wemby, Collins, Barlow
This should help the Spurs compete for the playoffs, at least without having to give up on the picks to other teams as they could get Brogdon, Moody and George in free agency itself. If George costs them a lot, they can settle for Tyus Jones as PG and any decent SG backup.