Anyone who plays ADOM for a while probably found themselves in a situation where towards the end the game stops being challanging. The Char becomes so powerful that only carelessness can kill it. I know that there have been many efforts to fix it but IMO little has changed. Right now I am playing Mist Elven thief it is level 33 that I planned for ultraending. This can be considered as one of the most difficult combos to play with... yet still I found myself in this awkward spot that I lost interest to finish the game, since I do not see any challange in continuing. The char became overpowered. I made an effort to diagnose what is the reason behind it and here are my thoughts:

1. Teleportation - This is single most significant culprit of late game boredom. Despite the effort to make it less potent, this is still the most OP spell in the game. This is like out of jail free card in most situations.
Solution:
- remove the guaranteed wand of teleportation from the guild of assassins cave
- wands of teleportation should not be chargable with potions of booze (as an exception). Scrolls of charging, potions of mana etc. are fine. However, potions of booze should not work, since they are easily accessible and basically unlimited.
- books of teleportation should be made even more rare and Khelly should not give you a book for the amulet
- casting the spell should have some kind of adverse effect on you, simililarly to casting Wish. My suggestion is that it should drain your stats similarly to how casting from HP drains your stats.
- items of teleportation should ignore "teleportation control" instrict.
- give some monsters the ability to forbid your teleportation at all if they are present on the level.
Basically, teleportation should become luxury not comodity.

2. Decreased item drop rate - yup. You hear me right. RNG should be less favorable to you. This is a consequence of the game becoming longer. There are much more dungeons to explore these days. I.e. you have 6 random dungeons on the map recently added. As a result, if the char chooses to explore everything on the map before going deep into CoC this char will be just overloaded with items. I really mean overloaded. In the current game I decided I want to explore everything on the map. By the time I reached ToEF I was almost level 30 and have found 10 potions of gain attribute! Without any sort of grinding. I simply explored all the possible dungeons.You hear me right! 10 PoGA before even getting my first orb. This is just an example but this goes with all sorts of of items. I have some enormous stash of potions of ultra/extra healing, countless types of wands including wand of paralization, death, destruction and yeah... wand of wish. My equipment is so OP, that I am it is not even funny: robes of resistance, protector, adamantium rapier of devastation, seven league boots, celestrix, rings of regenerations etc.

Some might say that I had lucky roll with RNG... the problem is that it seems that I have this kind of lucky roll every time I play. Last time I played some two years ago my Mist Elven thief got his hands on skullcrusher (humanoid slayer). Combined with thief's level 25 class power this basically made the game broken. 70% of mosters were not even able to touch me in hand to hand combat... and the list goes on....