Talking with the testers today in my forums, I decided to change the way the experience level of avatars works. Instead of having a “multiplier effect”, which was causing avatars too powerful, I opted for a simple “addition”.
Each level will add +1 on attack and defence, and +5 on hitpoints.
As you can see in this screenshot, even the most basic and “harmless” avatar can turn into a deadly opponent once it reaches higher levels. Sure reaching level 5 means collecting 50 stones and that should take a while!