This is an issue I've been grappling with for the past few days. I brought it up with my girlfriend over dinner last night (she's familiar with ADOM but doesn't play), and we couldn't think of a good solution so I decided to see if the forums think it's a problem too, and if so see if there is a solution.
So issue is dungeon danger levels. In ADOM this is not a problem due to the fixed nature of the game. For a starting PC, I know ID 1-3 is a cake walk, as if the village dungeon. I know the Puppy Cave is slightly harder, and the small cave should be avoided after level 6. This continues for the rest of the game; I know that CoC is easy until maybe level 25, the ToEF should not be tackled before level 18ish, the Dwarven Halls can be suicide with poor luck, and the hardest places are the lower CoC and Emperor Moloch's home. There are no surprises and I know how strong I need to be before entering any area.
You'll see where this is going. Given that JADE is random, you'll NEVER know the layout or danger level of a cave before you enter it. The problematic nature of this situation is obvious. Let's say you get a character to level 8 and enter a cave. Perhaps this cave has a danger level comparable to the Dwarven Halls, and the first monster you see is an Ancient Liche who blasts you to bits. There's not much a level 8 character can do against a monster like that, and how were you supposed to know it was there?
What makes this problem particularly tricky is that every solution I can think of is flawed. For example, the game could be set up so that every cave within a PC's starting area has a low danger level. This might be the best solution, but it forces a certain element of linearity into the game. After all, you would have to do quests revolving around the nearby dungeons first, since otherwise you'd be risking too difficult dungeons.
The other solution is to have the danger level of a dungeon linked to the characters level when he enters it, or when he accepts a quest revolving around the dungeon. But these are flawed solutions too. I could go around every dungeon, enter, and leave to set a low danger level and come back when I'm much more powerful. Similarly, I could accept many quests, setting a low danger level, and do them later when it would be a cakewalk. So dungeon danger level should be fixed.
The others solution is to make all dungeons like the CoC, in that they start easy and progressively get harder. But this makes no sense either. Some dungeons should be hard from the get go, otherwise high level pcs would always have to slog through a few levels of kobolds. There should be dungeons difficult from the get go.
I have one solution. If a dungeon danger level is very high compared to your level it should generate a message (if your perception is high enough) like: "You get a feeling of intense dread" or something like that. That way, your character gets a fair warning before becing stomped by a moloch.