To me it seems the most over powered aspect of the game currently is the Spy summoned creature. If multiplayer launches with this creature intact there would be no reason I would ever choose the Kingdom side.
Think about it. It's a relatively easy creature to get and has an immediate AOE that does 10 dmg to everything.
With the current health pools of the Champions you could easily take out 4-5 Champions AND the Sovereign within the first 2 combat turns.
Can anyone think of a balanced ability on the Kingdom side to counteract this creature?