oh yes I miscalculation the rowdy dwarf.I have no idea how you reach the conclusion that Munro can do 27 points.
The only explanation would be that you count the transformation of 2 point units into <=7 point units as 7 points.
If you do not ignore the 6 points of the transformed Rowdy you get to the conclusion that he is worth up to 21 points, which is about what you stated would not be too strong. Not to mention that he requires slow, random damage and combo pieces to set up the Rowdy Dwarves.
Based on that I would argue Munro does not require any kind of nerf.