All of the purely mechanical changes to the game (movement, animations, combat and the UI for example) I really really like. Especially the UI, reminds me a lot of Bizarre's Blur UI.
I would really like to see more of the non-mechanical aspects; lore, enemies, environments. So far they have revealed a small amount of that kind of stuff, and naturally to avoid spoilers they should. But I think a decent overview of some of the links to DA1 and the intermediary time period might be nice.
I'm totally sold on the game, and a straight live streamed run through is, I believe, one of the best ways to market a game. They did a similar thing with Civ V, and before that with Red Faction.
I think fans just want to see the game played. Not vertically sliced into an edited trailer or teaser. It really assuaged a lot of my niggling fears, mainly over how the combat would work and the new class relationship. I hope BioWare learns from the marketing for Dragon Age 2. I think it has been haphazard.