I'd rather have a new point guard, but I also think Vince could get this team out of the second round.
My only reservations with this trade if it were to happen is that we would be losing dept in the front court in a way that might negatively impact the flexibility of the lineups we can throw at opposing teams. I'd be a little more comfortable if we were getting at least one serviceable big along with Carter. Other than that, I agree with lala that he probably fits with this team much better than Artest. I see him as a natural, almost perfect fit for Adelman's read-and-react schemes, able to move without the ball, exploit mismatches, and while not McGrady-esque, his passing is much better than Artest's. But the one thing I would crave him for the most is his crunch time efficiency. That one thing the Rockets have lacked since before McGrady's last round of debilitating injuries is a guy you could give the ball to with the game on the line and count on him to make things happen. Vince is that guy, and that alone makes the trade worth it even if at the expense of frontcourt depth.
This year his performance at the 3 has been rather abysmal, but I suspect that's a function of injury and poor sample size. Historically though, you are right -- over the past two seasons he has been the most productive at the small forward position, even though he was designated as shooting guard.