I think, much like musicians, producers also have their peak where they find their sound and the sound that fits in its time and then also fade a bit. As others have pointed out, a number of more recent Bob Rock productions, I didn't enjoy sonically much either. Hell, St. Anger is over 20 years old and I hated that (haven't listened to it for what feels like a lifetime).
The only thing I can "accuse" Shanks of is having introduced Bon Jovi to the "wall of the sound / all done on the fly" type of recording and production. Jon said in a EPK for HAND that Shanks was the first producer he shut up, just sat back and let him produce the songs (sound like he was more of a pain in the ass on albums prior to it
).
That sound was quite popular at the time, but hell, HAND also is two decades old by now, times have changed. Maybe Jon grew comfortable with it, but Shanks could've brought new sound or production ideas (especially as he's part of their line-up by now) to the table as well.