There's a lot of things I want in Dragon Age 3, and I don't expect to get it all, but I still want to throw my opinion out here.
Changes:
Loot System- The loot system must go back to the one in Origins. I much preferred being able to inspect a weapon or piece of armor in the loot screen. I liked the tiering system in the first game as well. All weapons named "Dagger" had the exact same stats on it if they were the same tier. I don't know how much time I wasted on my first play through going to the inventory screen to see if the weapon I just picked up was better than the one I had.
I want to be able to inspect it in the loot screen and I don't want one normal red steel dagger to have +5 attack and another one exactly like it has +2% attack speed and +8 attack.
Specializations- I want more variety in specializations. I like how they expanded upon them in this game, but there were only three after the six we had in Awakening. For Mages, I extremely enjoyed the Force Mage but I was disappointed that Arcane Warrior was gone, as were many others. For Rogues, I liked all of the specializations but sometimes, I just really wanted another option. Same with warriors.
I would like for there to be one or two more specializations for each class in Dragon Age 3, new or old ones. I don't really want Spirit Warrior or Arcane Warrior or specializations like those, because, even though I really liked them, I felt like they were overpowered.
Combat System-I liked the one in Origins a little bit more than the DA2 system, but I think there is a balance between them. I felt like Origins was a bit slow and DA2 was a bit fast. Dragon Age 2 just seemed unrealistic with how mucb ease and speed Hawke could swing his two-handed sword, while in Dragon Age Origins, it seemed like Sten would just sort of throw his sword at the enemy and not swing it. However, the mage attacks, I liked. Staves actually were good weapons in this game and the spells looked awesome. For Rogues and Warriors as well, I liked the design and speed of all of the talents like Twin Fangs and Mighty Blow.
Map Designs-As we all know, there was little variety, if any at all, in the environments. I didn't like going to the same entrance for two different locations.
Character Creation- I liked the default Hawke, but on some characters, I just didn't want that look. I know there were different presets to choose from, but I got used to the look of Bethany, Carver, etc. and didn't want them to change. I can understand if I make my guy look completely different from the original Hawke, then, sure, change their look too. But sometimes, I wanted everything the same besides the hair style, facial hair, or maybe a little difference in hair color, but I couldn't do that without changing all of their looks, which I had gotten used to by that point.
Weapons and Armor- I was fine with this for the most part, but I felt there should be some more designs for the unique ones. And for the unique kind, I think their inventory portrait should be different. In this game, I just didn't feel the satisfaction of getting an awesome weapon when I found it because it's portrait looked the same as the normal kinds.
Random Encounters and Travel System- This was a huge disappointment I feel. In Origins, sometimes I felt like there were too much encounters, but in 2 there were close to none. I also preferred the travel system in Origins more. I never liked the shifting between screens and staying in one city and area for the whole game.
Companion (Chatting)- I enjoyed the companions in this game. I also really liked how in each act, their own personal story kept advancing. The only thing I would like to see is the ability to strike up a conversation with them, just to get to know them better.
Dragons- I liked that more dragons were in Dragon Age 2. But, as we all know, dragons drop (or should drop) the best loot. The High Dragon in Act 3, I enjoyed. The battle, the loot, everything. However, some of the other dragons dropped nothing good and I was let down by that.
Bosses- The only thing I want changed here: Go back to putting enemies names in different colors. There were multiple occasions on my first play through when I didn't know if something was a lieutenant or a boss, or a boss or elite boss.
Decisions- Such as being a mage, templar, assassin, those sort of things. I went through a play through as a templar, and it may just be me, but in no way possible should Anders have liked me at all. Also, if I'm a mage, why aren't the templars ever coming after me? They definitely know I'm a mage, so shouldn't they do more than pretend I'm not a mage? And, if I'm an assassin, I don't think my companions should trust me as much. Like in Origins, when my companions were against Zevran joining my team, because he was an assassin.
The Deep Roads- I loved it in DA2. I thought it was overkill in Origins. I want to explore it more. Like Nathaniel Howe said, Hawke's expedition was the furthest anyone had ever been in the Deep Roads. I want to find more out about it.
Ideas I want explored:
These are just the ideas I want brought up in the game. I don't care about these being the main plot, but at least bring these up:
Morrigan/God Baby
Mage/Templar conflict
Qunari
Architect (If he survived; even if he was killed, I'll be surprised if they say he didn't live or is just out of the picture)
Seranni (Yes, Velanna's sister)
Dragons (There were more in Dragon Age 2 and I like that. But why did everyone think they were extinct and, now, for the past 30-something years, they are popping back up again? Something seems fishy...)