in my honest opinion, he should not lose the weight. The reason why I say that is because he is physically stronger than probably 80-90% of the guards in the NBA. 6'4 @ 220 lbs, and I believe his bench press at the draft combine was absurd. He is very strong guy. Also, I don't think he's in our top 3-4 when it comes to offensive usage. IT of course will have the most touches and offensive opportunity than anyone else on this team. Then I see Bradley and Sully on top as well. Crowder is also stepping up his offensive game from the last 5 outings. I believe in another thread, Smart averages about 8 shots a game (someone confirm). That's not a lot, and he is still averaging almost 10 ppg.
I've seen him post up smaller guards with success and ease. And there are other players who are considered "too big" or "not athletic" for his position. Paul Pierce is an excellent example...besides LeBron, Pierce is a pretty big at the small forward position and isn't exactly the most athletic but still a great scorer. Someone mentioned Lowry, yea he lost a bit of weight but he is still a strong guard. Marcus Thorton whom a lot of people think he is overweight (I actually thought this is funny lol), is also another example of a big (or even out of shape lol), guard who can score.
His weight isn't also limiting his defensive skills so therefore I do not think his weight is much of an issue. If anything I think it gives him an advantage.