My main criticism of slaughter wads is never about the difficulty. It's more of a secondary criticism, because the Doom community is mighty autistic and some well-known imbeciles have no ceiling on how unforgiving a map can be. It's almost like they want to make levels for a TAS run, then normal players.
Otherwise, when it comes to hard normal maps, if i'm having trouble i will just lower the difficulty, or retreat in defeat. When it comes to slaughter maps, my main issue is the length, the grind and poor pace, the overreliance on rockets and bfg, the repetitive nature of the combat and the visuals, the retarded modern texturing tropes, the fact that they are being seeing as "art" when they are in fact utterly moronic, and so on... I guess i rarely mention the unforgiving difficulty, because i don't play these fucking things in the first place. I know what they are, i know i'm not going to like them, so why should i even give them my free time?
The early maps, up to around 12-13, of NT look impressive. They are some of the nicest looking tech bases i've seen in Doom, and they are not full-on slaughter, but they are still boring and exhausting to play. The pace is awful, and if you pistol-start them, they force you to kill dozens of mid-tiers before they give you rockets or SSG. That FrackFRAG guy said they were trying to give the maps "a Doom 1 feel" by not giving you SSG by the middle of Map05, except there's nothing Doom 1 about these maps, when you have to shoot mancubi, arachnotrons, HKs and revenants with nothing but a single-barrel shotgun and a chaingun. It's such a retarded thing to say when trying to defend a poor design choice. Hey, dummy, if you wanted to give these maps a Doom 1 feel, why didn't you use only Doom 1 monsters then?