Seems like a big muck up on Intel's part. Sounds like everyone is having one issue or another with HD4000 drivers and 8.1. Really big disappointment. Add to that there doesn't appear to be any updates / news on what is being done to fix it.
Looks like Intel and Microsoft heard us. They released an update on the 19th that fixed all my issues, it was delivered through Windows Update. Hopefully this works for everyone else. Thanks Intel + Windows!