The trick with Slayer is that when they first started out they were very unique and had their own sound. I'm not sure at what point their albums started being Slayer-by-numbers as I lost interest in them when they put out Diabolus (which ironically was a change of sound, just a very very bad one) but every time I hear anything off any of their recent albums they sound like tired rehashes from a band who can't experiment, because their fanbase won't let them, but are happy not having any new ideas.
I have a great fondness for early Cannibal Corpse but they definitely peaked around 1994 and everything afterwards is technically very tight and brutal but also a bit uninspired. I genuinely couldn't tell you the difference between albums after a while, which is when it's probably time for a band to stop.
Anyway, I'm glad ND aren't treading this path!