It is strange that LS and RS overlap and even conflict. I thought LS would only control movement and RS would control all dribble moves.
I didn't really get the point of the RS at first since it didn't offer many new moves and took away sig size ups, but one thing it does is isolate dribbling input from whatever you were doing with the LS and help pull off some moves a bit more consistently. In 2k12, I often had difficulty doing behind the back moves if I was moving my player around and his orientation wasn't clear. 2K13 helps a little, but it's unfortunately offset by the fact that between the legs dribble is diagonal back and sometimes you trigger that instead.
One way to fix this and address the overlap of moves on LS and RS is to have spin on LS be spin move and half circle on RS be behind the back dribble. This eliminates the problem with accidentally triggering between the legs and even makes more sense conceptually-- you spin the LS to actually move your player in a spinning motion and move the RS in a around the back motion to dribble behind the back.
It also has the added benefit of resembling the control scheme 2K games have had for years. It also opens up the back mapping on RS though it might be a good idea to keep that open or allow moves only in certain contexts to prevent it from being accidentally triggered instead of the between the legs dribble.