Just some thoughts on future abilities:
Cure/Heal poisons.
Heal diseases.
Bring someone out of unconsciousness.
Raising dead I think would be the ultimate ability having a high rank in the guild and much skill to perform such a task. I think it would help players be a little more cautious about how they handle themselves (if death is going to be very costly) since healers that are able to ressurect would be difficult to find.
Post some thoughts if you have ideas.
Abilities
As the heal class, maybe something to improve warding chances against poisons/diseases. Also with herbalism being a pre-cursor to healing, at least historically, maybe something to improve foraging skills, self cast only or cast on others, ....either skill with a set amount of time it's active (maybe the same as buying skillup practice)