Just saw it myself. A lot of it was more sharing of their thought and decision-making processes which is cool I guess.

Notably it's the second mammoth expansion which will have the free single player content. Maybe the third also, the damn thing was an hour long, but it seems like they'll process feedback from the first try before deciding anything.

They also stated that the SP content was going to be more difficult since the rewards are packs instead of specific cards. Whereas the non-heroic adventure fights could not be too difficult since that would mean weaker players paying gold/money and not getting anything.