Either I've been extremely unlucky, or currently common shops only offer items up to lvl 15. I would like to get some lvl 18 items from them, as they are quite hard to come by. Hard to say how much it would affect MP balance, but I imagine effect wouldn't be that big, as most of the high level commons/uncommons aren't all that much better than lower level stuff, just more situational/specialised. And they require major power token anyway.
