Don't know if you have the answer to this, and I feel like I heard an answer to this years ago, but maybe you can give some insight...
Why weren't MMs given two face prints for heads? With most characters having hair that covered the back of the heads, and this being a somewhat common practice for Lego, why wasn't this utilized in MMs more? Sometimes we were given multiple heads for a character but still only one print per head.
Obviously not every character needed multiple faces but would have been cool for many characters.