If the Big XII took six from the ACC it would be a pretty smart play. You remove your competition to free up more dollars for your member schools, protect your conference long term, and can go to a true two division/conference setup which would give you more potential playoff teams.
The only way this would be good for us is if six teams go from the ACC and UNC is not one of those six. UNC goes to the B1G and somehow Utah gets invited to keep the numbers even. Then there's one more spot in the Big XII