I really don’t think Blizzard gives a damn about people taking off for their expansion launch. That alone sounds ridiculous, taking off because of a new expansion - I know people do that stuff, but why should Blizzard bother about this, in the end it’s still a decision made by people Blizzard has no control of.
As I said, it’s very unlikely, but we’re still in a very weird year. A delay of the expansion is something I wouldn’t find as surprising as most other stuff that’s happening. Likely? No. But there’s no better time than 2020 to pull it off, due to [insert reason].