Clockwork Knight
Arcane
I still think an easy mode would just add more viable builds, and make players complain less about the meta-gaming aspect, without necessarily making the game a lot easier in the process.
So you want to add an extra game mode to stop people complaining about meta gaming, and you want it to be an easy mode that barely makes the game any easier?
Fallout does this. The "Easy" setting just gives a slight boost to your skills. 10 or 20% I think.