Offensively, SF is a tough position to build around, unless you're a point-SF like Lebron or Bird, tbh..even Durant, a generational talent, has had his team's strategy constantly questioned because they don't get him the ball enough..
The Spurs' post-2011 system is entirely built around penetrating guards/pick&roll guards(Parker and Ginobili) and finishing bigs surrounded by spot-up shooters, tbh..even this year, with Kawhi breaking out, he was still largely ignored by his teammates and put in poor situations during the latter part of the Clippers' series..it's still a work in progress, as they didn't have time to implement it with all his injuries earlier in the year..
Kawhi improved his passing, still a work in progress, but that's something he will have to continue doing..
The current team is built pretty poorly, though, especially if Leonard is going to be a focal point..the PG can't shoot, Duncan can't shoot and Splitter can't shot, awful spacing..
I don't think he's a #1 guy, but the Spurs have already shown they can win without a conventional superstar, and while it is very difficult, it's probably just as difficult to find a legit #1 guy to build your team around, too..we've been fortunate to have Tim, but they don't come around too often..the Spurs won't win another le with Parker on the roster, anyways, so they just have to ride out the end of his contract..
Fortunately, Leonard is one of the 3-5 best defensive players in the league, always a nice fallback when the offense is struggling, as long as you keep him involved(as is the case with virtually all players, even defense-first guys)..