Okay, I think I finally decided what abilities to go for:
High Sorcery to 100
Natural magic to 100
Battle to 75: Done
One more skill to 75.
Stealth/Empire left at 0.
That one last skill is probably going to be vampire. However, vampire seems to benefit physical characters more than casters, and getting survival to 75 doesn't seem to benefit much either. As for trade, we have several characters that are much more specialized.
So for High Sorcery:
Arcane Power
Disenchant
Enchant Weapons
Enchant Armor
Enchant Tools
Greater Enchantments
Manashield
Mirrorimage
Sunshock
Phoenix Rite
Foresight
Staffmaking
Powerful Staves
Staff Mastery
Siege Ritual
Enchantment is there as it's a full tree, and enchanted equipment is always useful. Staff making is necessary for staff master, which translates into caster power. HS doesn't have much in the way of attack spells, so they're there. Sadly, I do lose out on Vigor, but riding will hopefully alleviate that.
For Natural Magic:
Fly
Heal
Cleanse
Purify
Heal Friend
Eartharmor
Heal Party
Rejuvenate
Ready Fireball
Hasten
Lightningbolt
Skybrand
Solar Power
Gift of Nature
Familiar
Counterspell
Not much to say here. I could probably dump 4 abilities and take the healing potion tree instead.
For Battle:
Cloth Armor
Endurance
Reflexes
Disarm
Medium Armor
Shield Block
Block Arrows
Quick Block
Sparring
Finesse
Leather Armor
Stunning Blow
Nothing to see here, just buffing stats.
A lot of this rides on how well damage scales with int. While H2H requires str and dex, and anything with stealth also use charisma. I can throw seashells on everything I have and hopefully that'll drive my power up. And there's still that last 75.