Ok, so surprisingly enough, I'm still working on my roguelike, the Legend of Siegfried. For some reason I don't see it listed in any of the changelogs, but in one of the previous versions I added "Special skills" or feats (in ADOM they would be called talents... I suppose class powers would fall under this too).
For example, characters of the mercenary background begin the game with the Shield Bash feat, which allows them to sometimes make an extra attack using their shield, if one is equipped. Right now there is no way of acquiring new feats after the start of the game. There are several ways that could happen:
1) On level-up, or some similar significant character advancement, you can choose from a selection, based on your character's level, stats, skills, etc.
2) Feats may be granted as quest rewards, independent study, or other one-time only specific events.
3) Masters of various professions might offer training in various categories of feats; in order to gain the feats from them, of course, the character must meet their prerequisites in terms of skills, etc.
4) Other ways I'm not thinking of right now
Probably all of these will be used to some degree in TLoS, but I also want to make one of them the regular or usual method of acquiring new feats... but I don't know which is most appealing in terms of game design that allows flexibility, depends on your previous choices, and yet isn't frustrating or disproportionately difficult to form your character the way you want.
What do you all think? ADOM, Incursion, ToME 4, etc. proceed mostly, if not exclusively, by (1). I'm just not sure yet if I want that, so I was wondering what other players/developers thought about it.