I had this idea after kicking a certain goblin statue and getting permanent invisibility at a very early stage of the game, well before arena or precrowning.
Since potions of visibility are so rare, perhaps a feature could be implemented to have a cursed amulet of light make PCs visible?
It wouldn't hurt the balance, it wouldn't give any abusable advantage.
Currently invisibility has obvious beneficial qualities but it makes some things in the game either impossible or very tedious.

This RFE would also be thematically coherent.
After all, a source of light that can make whole dark rooms bright again, should be easily noticeable by monsters and thus pinpoint player's location in a dungeon.