Suggestion
The Greater Identify spell (or its scroll equivalent) could give additional details about certain items in the game. For example:

Using it on the emerald dagger "Serpent's Bite" should tell you "It poisons monsters on successful hits." like poisoned weapons.
Using it on phase daggers should tell you "It ignores all the protection of your opponents." like weapons of penetration. It currently says nothing at all.
Using it on weapons of mayhem and devastation should say "It causes two extra dice of damage when hitting an opponent, and its hits are more lethal (+6 to damage)." and "It causes four extra dice of damage when hitting an opponent, and its hits are more lethal (+6 to damage).", respectively.
Maybe, using it on weapons of the void should say... that it does whatever it is that weapons of the void do. (The consensus seems to be they scare opponents, but I haven't had much luck triggering that)
The following items do not "help to increase the -foo- skill" like e.g. cooking sets, and it feels like they should:
* Thieves picks (Pick locks)
* Climbing set (Climbing)
* Hatchet (Woodcraft; can be put in the tool slot)

Why it'd improve the game
Telling us the special properties of items (if any) is what Greater Identify is supposed to do in the first place.

Notes
It might be argued that no one uses Greater Identify anyway, but that's because we're spoiled. I believe this should take a minimal amount of time to implement anyway, hence not delaying ADOM 1.2.0 too much :)