I'm glad this is at least getting looked at, regardless of the final outcome.

The current magic system is, in my opinion, need of some slimming.
As far as some of the weak and/or missing spells... a couple ideas off the top of my head:
Body:
Enlarge (if you can do the visual to go along with it, otherwise Strengthen) - Adds Strong promotion until the unit's next combat
Chaos:
Word of Chaos (temporarily charms/weaken/confuse a random target within 1 square radius)
Creation:
Create Potion (requires mage be in city, perhaps with mage guild or alchemy shop, costs 10 gold, creates randomly selected: 50% heal, haste, hide, or heroism (1 xp))
Create Homonculus or Familiar (mechanically I'm thinking similiar in effect to stoneskin, though maybe increases xp, or? dunno, just a random thought)
?name? (creates an random, though appropriate (per xml) bonus on current tile, can't be recast normally, is instead "un-greyed out" by event)
Earth:
Spike Stones (can only be cast on hill, either creates a zone of negative healing on current hill and surrounding hills, or summons creature with something like 1 str, 6 first strikes on the same areas)
Move Earth (move a hill in the direction you're facing to your current location)
Rock to Mud (all creatures except flying in radius have movement rates temporarily reduced to 1)
Entropy:
possible new effects: minor damage, but loss of a combat promotion or two?
damage all living creatures in your plot and the plot in the direction the mage is facing?
Force:
Shield of Force (+2 defense strength until next combat)
Wall of Force (similar to Guardian Vines, immoble high strength unit that has a limit to damage can deal)