Yeah...I don't (have access). But, Razjah, if you'd like to throw some suggestions at me, I'm ready!
Nellsir, with the goal of creating a simple, core system, Socialize might actually work as a skill. Same with Knowledge; I can probably draw up abstract rules that fit any specialization a character can dream up. Something like this:
Knowledge (category) - Mental-based skill. Knowledge is the skill used to represent things that your character knows that you, the player, do not. Knowledge can be used untrained (without special education). When you take the Knowledge skill, it applies to a general field, like the topic of a textbook, for example, Nature, Magic, or Society. Skill checks look like these results:
10 - general or common knowledge of the subject.
14 - amateur study.
18 - professional study.
22 - obscure knowledge.
26 - sage only.
30 - godlike sentience.
So with real broad categories, the skill list starts to look like this -
Fight, Parry, Cast Spell (name), Knowledge (type), Profession (type), Sneak, Detect, Concentrate, Spirit, Repel Undead, Movement, Handle Animal, Perform, and Socialize.
And the sub-skills for game-groups wanting more specificity:
Fight: melee attack, ranged attack, wrestle, disarm, trip
Parry: dodge, block
Sneak: move silently, hide, pick pockets, pick locks
Detect: spot, listen, search
Concentrate: used in my system to defend against mental attacks, but includes focusing, maintaining spells, etc.
Spirit: used in my system to defend against metaphysical attacks, but can include anything ether-related
Movement: climb, swim, fly, sprint
Handle Animal: ride, train, calm
Perform: play instrument, act, use bard music, recite
Socialize: diplomacy, intimidate, bluff, gather info
But I'm brushing up against a fine line here: if your skills get too simple, they start to resemble your abilities. So you might as well just add bonuses to your abilities, instead of having skills. So skills must be somewhat specific, just to differentiate them from abilities...