I actually don't feel there is much filler; Wall is pretty great musically, but it's too damn depressing. Not that other albums don't have some heavy subject matter, but I can only listen to Waters bitch about his mama so much.
I much prefer Momentary Lapse of Reason. It's like a breath of fresh air after the stifling Waters finally left the room. If it were up to him, the whole band would have coasted on the success of The Wall and would've become stagnant just as Waters did during the last 40 years of his solo career. It's too bad he can't get past it.