Bride of Frankenstein would be ideal for a line like this (ditto the Phantom of the Opera), but it's entirely possible that the widely recognizable aspects of these characters (tall "lightning bolt" hair, half or full face mask, etc) would infringe on copyrights owned by Universal or Lloyd Webber etc since they created certain aspects of the character or portrayal of the character. I'm willing to bet these iconic designs were among the first listed as possibilities when the line was first conceived by Lego, but almost certainly ran into legal / intellectual property conflicts at some point. It stinks but that's how it goes sometimes.