Well, it will help you understand what dark Munich tastes like... I'd agree with Jeff that a dunkel is a better choice. I think if the gravity gets too high, the dark Munich can be pretty intense. Look for a bread crust flavor, sometimes with a toasted crust note. The graininess can get out of balance and sometimes it can have an astringent note. But it has a great flavor, quite unique, not very much like light Munich.
Back in the '90s, I made a recipe with 90% dark Munich and 10% aromatic that was supposed to be an authentic alt. It was so malty, it really swallowed the bitterness (50 IBUs of spalt). I loved the beer, but it really wasn't much like an alt.
So it can work to make a tasty beer but I'm not sure it will be something that kills the style. Depends on what you are targeting it for. If nothing else, you'll get a malt bomb that you can use to boost maltiness in other beers if you are up for some blending.
Give it a go. You'll learn something and you can probably use the result in several different ways.