Well, the reason Sacramento dealt Hedo was because he did not appear to be progressing as quickly as expected.
He came to the Kings as a guy who was capable of doing just about anything on the court and able to play all the positions except center. He left Sacramento with the same rep, except with the added caveat that while he could do just about anything on the court, he excelled at none of them.
The freewheeling Kings certainly allows for some freedom within its offensive structure, but it calls for sound decision-making by its players within that loose structure. Often, this left Hedo with a predictible move out at the three-point line that you could set your watch by. Not exactly what the Kings were looking for.
With the Spurs, this might work better, as they can be predictible in their own way, but that is probably what Popovich expects. I can see that he is right behind Peja in three-point shooting percentage this year. In that he has greatly improved from his days with the Kings.