In case anybody was wondering what has been happening with Witch's Wheel:
They're digging a big hole and that can only mean one thing! CP-TO-KI GIGA IN 2020!!!!1
But in all seriousness, they're probably just removing other infrastructure bits, like electrical or any sort of plumbing that may have gone to the ride.
Also...I tried to see what I could while riding Millennium Force and it appears that the splashdown in the back of the old Shoot the Rapids site has been filled in with cement (it may have already been filled in and I just never noticed). The earth moving equipment from one of my previous posts didn't do much apparent work - some spots look as if something has been removed between Millennium Force and the old site, or at least some bits have been cleaned up. More notably, the path for Dinosaurs Alive is about half gone - they've been ripping up the pavement since the attraction closed less than a month ago. This last bit is perplexing as I would have assumed that they would have reused the path for Forbidden Frontier. There's certainly much more for us to find out!