Hmmm. Fair thoughts. I'm guessing it's because the "M" is really subtle, and at times even hard to see.
I think I'll leave it for the time being and see what strikes me. It's a damn sight better than the BMW stock roundel, and it may take me a while to see if I like the thought of changing them.
If anything, I'd likely just fill in the engraved "M" with a copper matching paint.