Surprised no-one's mentioned the starting temple from Fallout 2 yet.

I think that's because it's pretty short, taking maybe 15 minutes or so.
But I agree it's bad, especially since it's supposed to be a tutorial area...that can easily get your character killed before the main adventure even starts. Particularly absurd is the guy who's using lethal force against you in the melee fight. That village would have deserved to perish for coming up with such a "test".

Yup xP definitely one of the more puzzling tutorial areas I've seen in a game. By kicking/hitting a scorpion once, and then using your remaining action points to move away, you could at least safely kite each scorpion. But of course that made the section even longer.
Iirc the 'dungeon' after that one wasn't particularly pleasant either: a couple levels deep mine with molerats if memory serves.

imo it's bad, because you don't really get firearms for a long time (apart from that crappy one-shot rifle), so you're forced into melee combat, even if you don't want to play a melee-focused character. Fallout 1 was better in this regard, since you started out with a pistol (and a knife iirc).

Oh yes, that pipe rifle thing in Fallout 2. I remember it doing decent damage all things considered, but could only be used once per round due to having to reload each time. I could make do, but mostly because I always go for a gunslinger character. Thankfully on all my runs the game started to pick up drastically after that mine level. Still, it's a good 1-2 hrs into the game up to that point.

Pistol in F1? Yeah it's definitely better, but even playing as a gunslinger I don't remember it being with all that useful due to the low damage and lack of ammo. Did ok against rad scorpions at least. However you were shit out of luck if you tried to take on that raider camp with it.

That reminds me of the "tutorial" dungeons in Arena and Daggerfall.

In Arena, you're told that you can rest safely on elevated platforms, but if you try to do that, you'll usually get a message to the effect of "you can't rest when enemies are nearby", even though there don't appear to be any nearby enemies.

Daggerfall's tutorial dungeon even has an enemy that can't be hit with weapons that are made with basic materials.

It also doesn't help that you're still weak at this point, and might not have the material you need to hurt that one enemy in Daggerfall's first dungeon. (With that said, that dungeon isn't hard to navigate, at least by Daggerfall standards, and as I've mentioned, it can be skipped.)

Your person and manifestations will take steady harm just by being nearby, and it will heighten the further you investigate. There are different regions where the very air has a harming impact, yet basically they are more modest or can be closed down.

This may sound strange, but anyone else always got bored with Baldur's Gate 1's Nashkel Mines? I tried playing the game multiple times, but for some reason never could keep my interest after that part.
Can't quite put my finger on the reason, but something about those mines, the story or design just bored me.
I know I talked with at least one other person, who felt exactly the same about those mines.

Something similar also was already mentioned with Diablo II's 3rd act. The first time I was hooked on this game and played it relentlessly. After that whenever i got to that act I was having less fun from it. I did soldier on most of the times, but I admit there was something off-putting about it.

Fallout 1 protip: If you go straight to Vault 15 as your first stop, you can get a hunting rifle (it's hidden near a toilet in a bathroom), which will make you absurdly powerful for a low level character.

Part of the problem with BG1 is the distinct lack of 'dungeons' in the first place. The original game barely had any. Most of the game was conducted outdoors and the interior areas it had were generally more natural areas like caves, mines ... not really 'dungeons', in the sense of being constructed underground interior areas.

I'm not saying it made it a bad game, but I felt the lack of interesting dungeons to explore was quite noticeable.

I was thinking the same, and I agree

You mentioned the Moathouse in ToEE, other people have already talked about Arcanum. As everyone probably is aware, both of them were made by Troika Games, along with Vampire the Masquerade - Bloodlines.
I haven't played Arcanum myself, but did play both ToEE and VtM-B and I definetly can say, that Troika gets much love for their games, as they are really good plot and atmosphere-wise, they are compelling and you can see the passion the designers had for them (even if ToEE is simply an adventure module from D&D), but at the same time there are a lot of bugs and badly designed areas/mechanics.

I found BG1 bad enough even so, and would say that having more "proper" dungeons would have made it even worse, considering its gameplay.

There's Ulcaster school and Firewine ruins in the main game. Both aren't all that great, not much content, and the narrow corridors reinforce the issues with the pathfinding AI. Firewine ruins is also widely hated for the constantly respawning Kobold commandos who tend to attack your party from behind and to pick off weaker party members. I usually avoid it entirely when playing BG1.
The expansion of course has Durlaq's tower, but imo that's also overrated, the "puzzles" in it are far too basic, everything is still very much combat-focused. BG2 had a better balance in this regard imo.

ToEE is the only Troika game I have played. It seems very inconsistent, with flashes of brilliance, but also aspects that are very poorly-designed. I have started the game several times over the years and never been able to finish it, as I end up getting bored/frustrated. The character development and combat engine are awesome, but otherwise the campaign is very poorly designed. I have pretty much come to the conclusion that overall the negatives outweigh the positives and it is simply a bad game. I want to like it, but I can't.

I would like to try Arcanum and Bloodlines at some point. From the sound of it, they both also have a lot of rough edges and I'll have to hope the positives outweigh the negatives in those cases.

There are no bad dungeons in WRPG. Simple. :)