I think if they dropped one hint that would be pretty cool.
I think the teasers usually work to build hype but in the case of Blizzcon we all know to just hype ourselves anyway.
I mean for all we know there is a hint out there for us, Moira was subtlety revealed in a comic before Blizzcon but so many other characters were in the comic that we ended up focusing hard on the prominent characters instead of Moira who we only got to see the arms and a mask.