To be honest, I find alchemy to be overpowered. The skill (acid pot and fire pot) do an incredible amound of damage compared to any spells. The acid bottle lower armor and can do more than 300dmg. It also seems to bypass earth resistance as well (can hit even with 100% resistance). It's like the lightning orb on steroid. The fire bottle do more damage than a fireball, and it affect an entire column. The animations are quick too, so there is no time wasted.
It does not do that much at first. The damages seems to raise with the character level. However, it is a nice early AoE. I always get alchemy as soon as I can. Especially since rep can buy the unstable concoctions. In early stage, it can change the battle since you don't have an army then and it allows me to clean the mobs with juste my master (alchemist) and it's assistant (meat shield).