Why would they want a PG? LeBron and Wade need the ball almost all the time. Why not just have them bring it up the court as the PG? Hell even Miller can play the PG spot.
The only thing this team needs at PG are good perimeter shooters and I think they have that in Chalmers and Arroyo..
If they are gunna trade Miller, I think they should trade for C. Not easy to find any decent centers in this league though that are tradeable.