Just have a big list of skills and let anyone learn whatever they want:
2157 Ride Horse in Combat
2984 Use Sword in Combat
3174 Bargain
[.etc.]
If you want, put a complex series of skill trees behind this and let
it affect learning times, so that, for instance, if you already know
"Use Sword in Combat" then you can learn "Use Javelin in Combat" much
more quickly.
And while you're at it, why not eliminate skill levels in the skills
as well? Or at least knock them down to something like 3 levels
(Novice, Veteran, Expert). It seems to me that trying to accomodate
10 levels stretches Olympia in some undesirable ways.
Of course, if it were up to me, I'd also eliminate omniscient
learning. You'd be able to learn some basic skills in any city, but
anything else you'd have to be taught by another unit, or RESEARCH it
at *considerably* more time and expense than being taught. But this
practically begs for NPC teachers, which may be too much to implement
at this time.
-- Scott T.