The idea of a library was suggested before, but I had an idea flash through my head that wasn't too overpower.
It'd be cool to have an old school spellbook in the game. ie. a crumbling spellbook with a bunch of different spells in it.
Basic idea is this. A random pop spellbook that can only be read once, but will let you study any non-drachma spell/skill you have at half your normal percentage. So you would have to read at least 4 to learn a skill.
Usage would be something like: read magic frostbolt
Extension of the first idea: sell personalized version in the quest shop for a drachma or two. 4-8 drachma for any skill is pretty hefty, and if they're not personal, folks will just make newbies to buy their skills.
The random pop ones might be cool to auction, if, for instance, they pop on valk more commonly. The newbies would have something to sell to collect money for their obsidian pearls. Through players with perm valkers might have an edge getting skills... dunno.
Anyway, some ideas for you.