Hey Speculaether, I appreciate the feedback.
Allies do scale with player stats (depending on their class, the scaling is different). It's not very visible right now but I'm reworking the ally system a bit and it should be extremely transparent next version.
I'm also greatly reducing ally purchase cost, but increasing upgrade cost. The goal is for players to play around with whatever allies they want.
None of the stats are capped right now (that includes attack speed and evasion), so things can end up being crazy / unfair / weird if it gets too high. That'll be changing next version as well.
Thanks!