For what it's worth, my opinion is that you may need to continue to play with the Munich malt percentage while trying various other adjuncts such as rice, honey, corn sugar (you already mentioned) until you get to a point where you consider the beer to be malty while still light and refreshing. The corn sugar will up the alcohol % and maybe lighten the body some, but I would bet you need to think about using some rice in your recipe if you want a lighter body, and then play with the Munich malt to keep it malty. Another option for the malty flavor could be some wheat malt, a very small percentage...just my thoughts.
Cheers!
Casey