I would not worry about the combat system. They say that the combat is one of their main focusses. And pretty sure those guys know what they are doing, considering their many years experiance in balancing multiplayer close combat in their cRPG mod of M&B.
Its also one of the main reasons for making their own game engine; to improve on it and make it even more addictive and skilled.
I would love to see what they can do with their own engine. Thats why i backed my few bucks and i dont think that i will regret it :)