I love this write-up and your suggestions. I think most of them are really good ideas. But since you asked for feedback, here are my thoughts:
Pyro - Increase the burning damage, increase the duration by 1 turn and have a chance to spread to nearby enemies every turn
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.
Hydro - Increase frozen duration and Have a chance to shatter frozen enemies below 10% HP
Love it!
Geo - Upon death, enemies release a poison cloud. Geomancer spells now inflict damage to both physical and magical armor at a reduced damage
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.
Aero - Each turn, a bolt of lightning strikes a nearby enemy
- How about lightning retaliation instead? Allow it to scale with Savage Sortilege as well so that it can crit, and chain a maximum of 2-3 times (but does not distinguish between friend and foe).
Hunt - The first attack against a enemy mark him. Until he dies, you do increase damage against him (you cannot mark more than one target)
Love it!
Scoundrel - Each attack inflict a stacking bleed effect for 1 turn
Love it!
Warfare - When you are attacked in melee range, you attack back
Love it!
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.
Summoning - The only one that already have a special effect at level 10
This one is great already. The "super incarnate" is really badass-looking and packs a decent punch. But the crafted infusion skill books make them even more badass.