Perkins isn't a "bad" post player. Surely, there are bigger stiffs and duds that stand at 6'10+ who can't do anything out there.
The problem with Perk is that he has maxed out. He deserves touches, but not at the frequency he's been getting them. The Celtics have been so inefficient offensively of late that their FG % leader (as well as the NBA's) was counted upon to carry the offense last night.
Anytime that happens is a recipe for disaster, with all due respect to Perk. Perkins is what he is, and an offensive option is just not that.
So the point is: Anytime you take a good player and take him out of his role and expand it, be weary of the end result. It won't often be very pretty. Perkins is a terrific complementary, auxiliary player, but when he's relied upon as a leader on both ends of the floor, your team will have issues. For Perk, the increasing amount of autonomy the Celtics have given him is new grounds for him even though he's approaching "veteran "status." He's the type of player who needs to be utilized the correct way in exchange for desired statistical input.