Exactly my feelings. I thought that it must be me at first, the fact that I found Eternal Doom IV a huge bore. Come on, I said, this is from the team that brought you one of your favorite wads, Eternal Doom III, keep playing, you must be missing something. I gave up in the end, hated the damn thing, and I'm cheered to see that I'm not alone in this. Never been more disappointed in a wad in my Doom life.
I beat Eternal Doom once, from beginning to end. Yes, some of the puzzles are insanely hard, and when I first started playing DOOM, that's all it took to get me to hate the whole WAD. Nowadays, though, I think puzzles are kind of a dying art in DOOM maps, so I learned to rather enjoy Eternal.
Eternal IV, on the other hand, is pure garbage. Yes, the maps are very big, but "big" doesn't automatically equal "good." It's mostly just a series of gigantic hallways with no clear idea of where to go, and even when you do know where to go, navigating said gigantic hallways is an unbelievable chore. This is one WAD that actually could really use regen health, because running around to find a random stimpack you passed earlier has never made me feel like breaking down and weeping as much as in Eternal IV.