Home Haunter, I have been doing this stuff for some 18 years now, and I have to say that is probably the coolest graveyard prop I have EVER seen. The movement of that thing is amazing. Speed, shaking, realism, the way his hands seem to press down on the grass. That is SO cool, and I am NOT easily impressed trust me.
I know what you mean about the simplest. My FCG, which I have not hug in some 5+ years due to weather, schedules, etc, has a motion tha tis amazing. It has red LED eyes behind clear glass "beans", and when the head swings and looks at you, the eyes get real "hot". One year, there was a steady breeze blowing right in its face, and its white linens were trailing backwards like it was "flying". I wish I could have taken a video of it.
Congrats on a VERY cool prop. All I can think of that might make it better is a motion sensor, and a really loud sound, (howl) when it starts up...!!