Bluetracker
Tracks Blizzard employees across various accounts.
Summary of the AMA
Here's a quick summary of the AMA. I didn't include overly vague things or where they said they were thinking about things unless there's some extra info past just that. Let me know if I missed anything important.
Firm Information
Players will be getting a new card, one week before the expansion
There is no Hero tied to the Year of the Dragon but there will be heroes this year.
There will be no new weapons for non-weapon classes in this expansion.
Teasers
Hints for the new keyword: two, twins, double down, spell
Hint for new Hero/heroes: shocked
Extra Information
They’re looking at how to best handle letting players obtain old card backs.
Combining collections across zones is a lot of work and not currently a priority.
The “Purple Rain” on the Karazhan board was a Prince homage.
Arena
These two posts don't really need summarising, best if you just read them.
Giovanni Scarpati
For this question I was specifically referencing a Hero like Lunara. Typically when we refer to Hagatha or Dr. Boom style Heroes, we call them "Hero Cards."