Personally, I believe he needs to do a little better than that to be viewed as a threat to score from the perimeter. Still, 33% would be a good start, and it's a long way from the woefully poor 20% he shot last season.
I think Sam's poor shooting is more in his head than in his form or release. He's not that far off from what I have seen. If his problem is confidence, he can overcome that by repeating his shooting motion until it is no longer something he has to think about. That comes from practice.
If he's not dedicated enough to take several hundred shots at least five days every week until the season starts, he needs to sit and let someone else take his place.
Sorry if that sounds too harsh. But we're not talking about rocket science here. Improving your outside shooting is about wanting to do it so much you you refuseto let anything stand in your way to get the job done.