I have a bevy of ideas. Probably none of them will see the light of day, but it's worth a shot.
A new branch of magic skills: Dark Magic
- Curse your target.
- Drain Life from your target and use it to heal yourself. I see it as a direct-damage spell, but it could become a vampiric enchantment of some sort instead.
- Slow your target down. Useful against those speedy clawbugs.
- Mass Curse.
- Mass Drain -- not only does it heal you, it heals your allies, too! And it drains from all enemies in sight. Very essence-intensive, though.
- You can be Clad in Shadows, making you harder for enemies to see and allowing you to be stealthy. Also makes it harder for enemies to hit you. And it even has its own (death metal) theme song!
- Kill is moved here from Battle Magic, being a death spell after all.
- Mass Slow. A powerful spell with many tactical uses. But very expensive.
To replace Kill on the Battle Magic roster, perhaps something like Blizzard or Lightning.
The ability to light enemies on fire (with the Flaming Sword, Aura of Flame, or some other such thing) and have them take fire damage periodically. But remember, you can be on fire, too. Basically, poison with a different name.
Expanded Item Forging. I loved this idea and thought it was a very nice addition to the game. Perhaps, though, some items could be blessable more than once, through the use of a rare and special tincture. Only really for items the player is pretty sure he's going to be keeping.
Having certain (N)PCs in the party could affect things outside of combat -- e.g. a loyalist NPC in a rebel camp starts making people very unfriendly towards you. Or taking a rebel character to that same camp gets him recognized by (and talked to by) someone in the camp that normally wouldn't give you the time of day, thus conferring bonuses of some sort (cheaper services perhaps, or insider info).
Inventories (or at least equipment sheets) for humanoid party members (humans and serviles).
A Crafting skill tucked under Leadership and Mechanics.
With metal bars, the player could be able to make non-magical items of their choice (increasing in quality proportional to the Crafting skill). "I'm not the most powerful person, but I can make damn good armor and weapons for myself! So there!"
If your skills in various fields are high enough, some NPCs might want to learn from you. Of course, you'll get cash or something in return, but you'll also draw the ire of the Shapers for selling restricted knowledge to outsiders...