Maybe many thinks the makeup looks amateurish? I think that's kinda the point. Hes just a maniac who paints his face.
I think the negative reaction to the makeup is that it's too far on the "circus clown" end of the spectrum. For example the red nose really makes it look silly, not maniacally sloppy like Ledger's or the evil simplicity of Nicholson's all-white face with thin red lips. Too much Ringling Brothers, if you ask me.