Not sure about #3, but in general based on the announcement it seemed like they showed just stuff relating directly to dragons + talents and UI.
Like a lot of info was shared later in interviews. Mostly regarding systems that would carry over in some for.
As my guess for #3, I would say perhaps the way we interact with the world? Dragonriding seems to be about that.
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Tyrande is said to play a role in 10.0. And also we will have to wait for SL to finish to get more info on this