One guy that definitely got worse, especially at demos, is Zakk Wylde.
Don't get me wrong, I am a huge fan of the guy, but every time he has some kind of solo show off bit, he switches on every pedal he owns and it sounds like mush. Worst case I can think of was the Marshall JMD:1 demo. Not awesome.
This hasn't appeared so much in recordings, but still. Someone should just take the pedals away from him live. Or only allow one modulation effect at a time, and never allow modulation and wah. OK, maybe chorus and wah, seeing as with Ozzy especially, the chorus was always on.
However, the two solos I have heard from the new album are not covered in phaser, wah, chorus and rotovibe. Good sign.