I'm quite disappointed also. I can't say it is a bad game, but gameplay has changed a lot and I don't like it. I have to say there are some things that I liked a lot compared to doom(2016): the less dark, colorful and B-movie style design; and the fact that with that design you can see more clearly where the enemies are in the arena and not get lost into it; more variety of scenarios; and the music is as good or even better than in 2016. The problem is that now the aiming and shooting is only 50% of the fight, the other 50% is chainsaw, blood punch, flamethrower, glory kill, ice grenade etc. They are not optional mechanics, they are necessary to beat the game (i.e: the ammo shortage is a constant) and I came here to run, aim and shoot. And the weaknesses of enemies... it's almost impossible to kill a cacodemon if it is not putting a bomb in its mouth, like other mechanics in the game, what could have been an interesting extra is just a repetitive thing you are forced to do again and again and again. Just to point how different the gameplay feels, on Thursday I finished Doom(2016) on nightmare difficulty, today I'm struggling and dying A LOT in the second mission of Doom eternal in ultraviolence.
The constant appearance of collectibles, challenges, cutscenes, tutorials etc. have been also a -minor- turn off for me.
It's better? It's worst? It is quite subjective, it's a high quality game in a lot of aspects, but the gameplay is very different to D2016, and some of us are not happy with it. Maybe if I get used to the new mechanics I find the game more fun to play, but I'm not the kind of person who sees 3 seasons of a TV show he doesn't like to see if it gets interesting on the fourth season, and I'm not in the mood to give doom eternal much more opportunities.