I quite like it. Only real comment is I think the moon is a little bright. (Yes, I know its really brighter !), but I think its a little overpowersing compared the the overall tone of the rest of the image. (or the cliff is a bit dark / blue maybe).
Of coruse, thats on the web, it may print just fine.
As for a composition, by your description, it was just a High-Dynamic-Range shot, blended for exposure, which is just a way of overcomming limitations on camera equipment. Now if you shot the moon someplace else, and put it in, then (to me) it would be stretching it a bit, but thats not what happend, so no issues !.
I was on Fraser Island for the full moon, and all I got was cloud