I know every poster in this forum follows the so-called "Spurs system" repeatedly and almost religiously, but a ball-dominant player is something that would actually complement the Spurs. Every role player on the spurs cannot create their own shot (maybe with the exception of Belinelli). The role players tend to do a good job with the floor spacing and the 3's, but a ball-dominant player can create floor spacing just as well (commanding mismatches and double-teams).
There's a reason people have been so disappointed with the Spurs not running plays for Kawhi; it's because Kawhi is not a playmaker, simply put. I think having another ball-dominant player on the Spurs can really lessen the offensive load of Parker and Ginobili, especially when posters get so mad when Ginobili turns the ball over.