The best approach is to just try it and see where it falls in with your tastebuds. For reference, I spoke with a number of professional brewers that I know and it seems like the trend at this moment is to lower maltiness for IPAs, pale ales, ambers, reds, etc. by cutting 2-row (or whatever other base malt is used) with wheat. If the trend is to lower maltiness, Vienna would be going in the opposite direction although you should not interpret that as MUNICH 2 maltiness. It's not like that. Vienna's L° rating is typically 3-5 so neddles is right... it's relatively light but there is something about its production that creates that deeper & maltier character.
My strategy with the recipe was use a more characterful base malt and then back off the higher amount of caramel often found in an Amber Ale. Then lightly hop it like an old school american pale ale.