I'm curious. Usually DLC comes in threes. In fact, I was a little surprised DAII only had two. The ME series had three for ME2/3. Of course, out of those, I'd say Shadow Broker and Citadel did the best. I've heard rumor...RUMOR, mind you...that Darkspawn and the Fade are the popular choices. The survey kinda goes along with that concept, a little different than what I was imagining...
PERSONALLY, and this is IMO, with NO EVIDENCE WHATSOEVER to back it up, but I personally think that the next two DLC packs will be:
First, the Darkspawn. We've touched upon the origin on the Blight, I think that we will dig deeper, potentially touching upon the next Big Bad of the series. Also, I think...or hope that we will touch upon what happened to whomever was left in the Fade. Another hope is that if we DO explore their fate, we will see a cameo by the surviving Hawke or one of their former companions. Again, that is a HOPE.
Second, the Dread Wolf. Also, Qunari. I think that the Qunari will factor into the next game in a much more impactful way. Like Assassin, they will delve into the Qunari, with a potential teammate who will offer a newer perspective on the Qunari. So far, we have Sten, Tallis, and the Iron Bull. They represent two of the three pillars of society. I think we might see the third. Unravelling the secrets of the Dread Wolf, and those who were directly impacted by their actions will be explored. ESPECIALLY if the Inquisitor has a personal motive for seeking them out.
I DON'T expect the HoF to show up. Do I think it could be done? ABSOLUTELY! They managed to give Hawke a personality, why not the HoF? A blank slate? ONLY at the beginning of the game. Besides, they already introduced the idea of personality through their actions. A ruthless monster doesn't do all those good deeds and save people. Nor does a heroic all loving merciful hero look at Branka, and go...'Hey, lets do that! I'm ALL for pouring molten lyrium on people! Start with Oghren! He smells!'
They pretty much established a personality through your choices already.
Those are my thoughts. Could I be wrong? It's VERY, VERY possible. Could I be right? Slim chance, but I can hope. 