I'm new and I've only done one run of DOS2 so far with a friend, but I definitely feel like contamination was a very underwhelming skill that seemed to be a bigger threat to my melee allies than my enemies.
As far as Geomancer skills go, I don't have any particular issue with all of the current ones spreading oil, but I do think it could use some more spells that focus on modifying the environment as opposed to dealing damage. Specifically I'm talking about spells that do things like denying line of sight, creating terrain that enemies have to maneuver around, or incapacitating them in ways that are not purely beneficial.
Earth Wall: Create a wall of impassable terrain for X number of turns (using wall targeting from DOS1)
Entomb: Selected target becomes encased in earth causing them to be unable to move or attack, as well preventing all damage done to them for X number of turns
Sand Trap/Unstable Ground: Place a hidden rune on the ground, when stepped on by an enemy the rune causes the ground to way, dealing X amount of damage and crippling the enemy for 1 turn. Enemies on elevated ground will be dropped below it if possible.
(I have the) High Ground: Create elevated ground at targeted location lasting for X number of turns.
Also, I like the idea of a Shackles of Pain that can be applied to someone other than the caster. In the run my friend and I did I picked Necromancy and ended up grabbing Shackles of Pain, but rarely found it useful. Granted, I was a backline mage and therefore wasn't getting hit a ton, but even when I found ways to use proc the damage - primarily through elemental effects - it was hardly as useful as I would've liked. Having the ability to link other combatants to each other to redirect or split damage would have been quite useful, and I fully support the idea.
