It's much more important for the Spurs to draft guys they think will be the best players rather than drafting for any skills. That's not the same thing as going for home-run swings on guys like Poku or Primo. BPA should have built into it a potential curve calibrated for the likely results at any given projection window rather than just the maximum value. For example, the Spurs should judge a player's shooting based on how good that player can become on that end and how quickly and not whether they can currently shoot. The Spurs still have to trust their developmental staff, or they have to get rid of them. They can't keep them but then not believe they'll do the job they say they will.
The Spurs do not have to be good next year. Fans and ESPN want them to be, but the Spurs actually have to continue putting themselves into the best long-term position, and that might well mean having a somewhat disjointed performance on one or both ends as guys continue to figure things out. If they draft Topic, Collier, Sarr, Buzelis or whoever else, and they can't shoot well next year, it doesn't matter. You want them to be positive contributors or at least show skills that would indicate they will be. If Sarr or Buzelis shows that he's too much for most centers to handle, that's going to add a lot of value to Wemby's growth, because it will make it harder for teams to cross-match a PF on him, since they opponent will be creating another disadvantage, making it harder for the center to come help Victor's man. If the guard is getting into the paint at will, that's going to help Victor by bending the defense, increasing the effectiveness of the PnR, getting bigs in foul trouble, etc.
Victor is not a finished product, not even in the broad strokes. We don't even know what position Wemby is going to play in his prime, let alone what type of player he's going to be at that position. If he's more of a perimeter player whose paint touches come mostly from slashing and transition, the team is going to need vertical spacing from Wemby's front-court partner or from the guards driving. If Wemby's going to be more of a mid-post iso scorer, the most important thing might just be a "running mate" he can take turns with ala Lebron and Wade/Irving or Durant and Westbrook. If he specs into being a roll-man rim-runner, a lob threat might be useful. If he's going to be a post hub, then spot-up guys and cutters might be more important. We don't know what that's going to be, and this season really hasn't provided clarity in that regard.
That's why talent (in the BPA sense, not irrespective of intangibles) is the most important criterion. If they draft the most talented player, that player might synergize with Victor and help provide clarity on where he goes on his developmental journey, or that player can become a meaningful piece in an impact trade down the road. I think it's short-sighted to draft with next year's team in mind. There are other ways to create a functional rotation, if that's even the team's goal. The team will not have everything figured out next summer. They don't need to operate under the idea that their pieces have to work together very well right away. There are a lot of paths the team can take to really start the reconstruction process, and they aren't going to all have the same results at specific increments of time.