Instead of a chance to spread the burning status effect, have burning enemies leave a trail of fire, or "bleed fire," similar to Fire Slugs.
LOL! I totally disagree! There's already a "Bleed Fire" skill, which is literally the most worthless spell in the game because
you never want enemies to run around at random spreading fire everywhere. Keep the damage as-is, but add in a chance to apply Acid with every Geomancer skill, as well as poison and earth damage from weapons. Also, the poison cloud idea is awesome, but I think it should be a small one.
Applying acid seems like a nice idea. As I said, the poison cloud is not because it's super situational and can backfire.
Polymorph - Dunno Increase the duration of your spells
+15% to all resistances
Necro - Enemies around you are weakened
How about a Decaying Aura? Perhaps one that only applies to enemies within range. Another idea would be to have a small chance for killing blows to instantly resurrect the enemy as an undead ally for
X turns.
The Polymorph and Enemy-only Decaying Aura ideas are pretty cool.