You know Haslem is the reason he isn't played more? As Jace has pointed out in game threads, Haslem hasn't been as good a defender as Joel for a few years now (Joel is basically a bigger, faster, and stronger version) and the one advantage Haslem had, his offense, no longer exists so you might as well be playing Joel.
We're actually a worse offensive team when Haslem is on the floor than when he is off. Also, opposing teams are scoring more when he is on the court.
I can't remember the exact stat, and who it was comparing too, but last year we were a lot better offensively with Joel on the floor than one would think. As long as we can figure out a way to not pass to him on pick and rolls, we can get away with it.
I don't know if you meant to quote me there, but while Joel shouldn't start, his contribution to the team is much better. Haslem isn't the defender his reputation says he is anymore, and the fact that he can't rebound in traffic, score amongst the trees, or now even hit his patented 14-footers makes him totally useless.
Joel can't rebound, score (though he's actually better close to the basket than Haslem now), or hit jumpers, but he adds a lot to a struggling defense, and sets great screens.