2011: Jimmy Butler over Cory Joseph with the 29th pick
The 2011 NBA Draft is often remembered as one of the best drafts ever, and it most certainly is. But it is remembered among Spurs fans for the Kawhi Leonard trade, which helped revitalize a team with a rapidly closing title window. However, it's easy to forget that the Spurs took Cory Joseph with their own pick, who went on to have a solid career.
Even then, he didn't play all that much of a role on the team until his fourth and final year before leaving for Toronto. As the 29th pick, Joseph exceeded expectations, but Jimmy Butler, who was taken 30th overall, far exceeded them.
The Spurs drafted Joseph because of a need at point guard, with Tony Parker entering his 30s at the time. But had they not, they could have taken Butler, who is in the middle of a historic playoff run with the Miami Heat.
Just imagine what Butler and Leonard would have looked like playing together, though that likely would have kept both from becoming the players that they are today. It also would have kept Danny Green from breaking out, which came as a byproduct of trading away George Hill. Still, this is all about dream scenarios, so we'll overlook that and focus on what could have been.