Aww no expansion

. I'll never get to make my sarcastic Hawke make fun of someone again

But working on DA3 that is something I'm excited on.
A few ideas that I have for DA3 is:
Sheathes - I don't know about anyone else but I find it a bit boring when everyone has their weapon on their back. This gives an interesting form of customisation, it can reflect companions personalities, and you should be able to enchant them to give your weapon an extra edge.
Cross-school abilities - I think having abilities that belong to two different schools such as crossing tempest with I don't know say ... crushing prison and it makes a completely new ability with features from both and with some new interesting features. This can be done with all classes.
Friendship/Rivalry - I felt in DA2 that you had to completely agree with a companion's point of view of certain topics or you had to completely disagree eg. Fenris in terms of Mages and Slavery. But I did like the fact in Origins when you treated your companions like dirt, most of them tried either leaving or fighting you.
Perhaps combine the two by having as a primary bar Friendship/Enemy and have another 'support' kind of bar for each thing that they have a strong opinion towards like Fenris and his hate for mages and slavery and they both have their own benefits.
Companions discussing choices made - It would add a layer of depth if your companions would confront you about a choice you made for an example you had to kill a child who wanted to become an abomination ... I don't know and one of your companions come to you and basically interrogates you about why you did it and also companions should discuss it during party banter too. It would make the player feel that their choices actually mattered for a while at least.
Fast travel, dungeon encounters - This would be a nice sidetrack from the main story as you can enter hidden dungeons and face slightly superpowered creatures for a chest of rare goodies. You can throw in puzzles, slaughter rooms (basically waves of enemies just come out of some doors and you just cut them down), quests and all sorts of things.
Simpler armour, weapon and item system - In DA2 the item system with the stars was just completely confusing and nearly a useless addition to the determining an items usefulness. Also I found it extremely difficult to make Hawke's armour (or robes) match without sacrificing his/her armour points. Perhaps go back to the Origin style of armour and give the player the ability to customise it to a certain degree.
That's all I have ... for now