Have you tried any of the graphical front ends for NetHack, like Vulture's Eye?
It's a lot easier to understand what's going on when a hallway looks like a hallway and a staircase looks like a staircase, though there is something to the simplistic appeal of the ASCII visuals of the original.
In the 11 years I've played NetHack, I have always only used the basic tiles that come packaged with the official release. ASCII is preferred because "DUDE IT'S THE ONLY REAL WAY TO PLAY, NOOB" but it really has no advantages over tiles. With tiles, you can always see if a weapon is a dagger or a longsword, if a piece of armor is a cloak or a worthless ring mail, etc.
I tried Falcon's Eye once or twice but really didn't like it, mostly because of the isometric-view and the fact that you can't see much of the dungeon on-screen all at once. Plus I actually found it way more confusing to have all those mouse-supported menus and whatnot.
Maybe it's just a function of having played NetHack for so long but seriously, the interface once you get used to it is just so intuitive and simple. In real-time, these days it only takes me about 4-6 hours to ascend a character spread out over 2 or 3 sessions.
I've finally gotten "pretty good" at ADOM - I've even won the game once - but there are so many parts of it that are just tedious and/or unfair. The monster spawn rate is ridiculous, some parts of the game can be basically unbeatable unless you have the right character or items (I'm looking at you, Tower of Eternal Flames), and it's kind of annoying that unless you want to totally gimp yourself every single character you play will end up using an Orcish Spear for the entire game, until you can find a better Spear, since all the other weapon class bonuses suck and getting weapon artifacts is, to say the least, a massive pain in the ass (and most of the weapon artifacts suck).
It's really too bad because ADOM could be a fantastic game if the author would release the source code and let people work on it, since he hasn't updated it since, what, 2001?