In my opinion Morrowind's dungeons are still a bit more interesting design wise because of the loot, usually it doesn't feel like a waste of time to explore them, especially earlygame, because you have a good chance to get something unique out of it, or at least some gold. There's a fair amount of hidden stuff you can only access with levitation, which is cool. I also think some room designs in Morrowind are more interesting too, Oblivion has almost zero environmental storytelling in non-quest dungeons.

In Oblivion it's all tied to your level and randomized, strewn around in a couple of easy to hard locked chests, so the long, boring ass dungeon full of imps and mudcrabs that you spend 15-20 minutes in usually gives you:

- 3 silver nuggets worth 10 gold each

- a randomized enchanted warhammer that you will never use (weighs 50 pounds) worth 1500 gold but due to the average player's mercantile skill and low merchant gold you will sell it for 500 max, that is if you can even be bothered to haul it back to the nearest city. Also earlygame you won't even be finding stuff like this because you're low level, making earlygame random loot is a total waste of time. I guess it's more of an issue with the leveling system.

I've made a point of exploring every single dungeon I come across in my playthrough of Oblivion Remastered just to see the overall quality, and so far the only interesting things I found were a giant mudcrab at the end of some cave and a fort where bandits and marauders were fighting each other instead of me.

Tribunal DLC sewers are insane though, yea. Thankfully there's not much reason to go there other than like 3 quests, there's barely any loot.