Don't confuse 'malty' with 'sweet'. This is a beer that should be full of malt flavour, but finish dry so that it is still refreshing and very drinkable in large volumes.
What BigEd says is "not dry, but the finish is". This is correct. Munich malt tends to finish with a higher gravity than other base malts, but the remaining gravity points aren't from sugars that taste very sweet to us. You are looking to have these 'not so sweet' sugars left, that lend a maltiness to the beer (from munich, dark munich, etc) but making sure the beer is completely attenuated in terms of sugars that lend sweet/cloying aspects (good oxygenation, healthy ferment, enough yeast, moderate to highly attenuating yeast will ensure this). Using crystal malts will give a more American version of a marzen - they tend to be sweeter and richer than true marzens. Caramunich is a bit less sweet and caramelly (a bit more biscuity) than other crystal malts in the same colour range.
I've brewer both versions (all pils/vienna/munich and pils/vienna with 10% caramunich) and really like both as long as they have that dry finish. I tried one that used S-04 yeast and hated it - the upfront flavour was excellent, but I couldn't drink more than one or two because of the sweetness.