Aww, now this is great! Oogie is one of my favorite villains of all time, possibly because he was the first stopmotion villain I ever saw. but enough rambling you want a critique right?
I find that this captures Oogie near perfectly. I like the different shades of green and brown for the shading, particularly around the head. It makes Oogie look a little raggy but oogie is a burlap sack, so it fits. The Bugs are also a neat touch, crawling out of the seams like that. The body type is perfect, As I've seen far too many Oogie ponies with a slim physique. He should be bulgy just like the original, and you've caught that factor. The Pose is also nice, If its supposed to be like when Oogie dances in the movie, you got it down with me!
While I aboslutly love this piece, there are two things I think that would improve it a bit more. the first thing is to add more of Oogie's characteristics, while I love the bugs I think you couldve added things like Oogie's snake toungue, dice, or spiders. The second is that maybe you could have added a bit more detail to the body. I mean Keep the shading but add a bit more texture, like he's a burlap sack.
Aside from those two small things this piece gets the closest to Oogie out of the other interpretations.
GOOD. FREAKING. SHOW!