He may be consistent, but he's not much better than Rudy, if at all. And he's much worse than Roy. So being the second/third string shooting guard isn't that great a use for a player making what he does.
The reason I brought up passing skill is because Roy is not a point guard. Yes, he is the one who controls the offense, but he's not a true point guard and, in my opinion, needs another passer alongside him to share some of the play-making duties. Installing Roy at point guard and Hamilton at shooting guard would create two problems: sub-standard distribution on offense and making every opposing point guard a prime Steve Nash as neither player can adequately defend point guards.