If your saying he has been a below average defender at the 3 his entire career then I would agree. How could you possibly want to see a player who can't play defense over Hill who can? Especially, knowing this team needs more defense?
Hedo is a pretty good defender at the 3 but gets pretty abused anywhere else(lack of quickness for 2s lack of strength for 4s). If he's worse than Hill defensively at the 3 it's not by much and no where near as bad as you're making it sound.