I think people pretty much already said it all, but I'll leave my recommendations anyway (in no particular order). It's a big list and I'm sure I forgot some things but cookies to those who manage to read it all. 
1. Give the PC a personality and backstory: I want to get to know my PC's story before crap hits the fan. It doesn't have to be like Origins, but at least show us where we come from and let us meet some characters from our past at some point in the game. Also, give us opportunities to shape our PC's personality while doing quests and interacting with the world.
2. More story, less exploration: 10 worlds is too much. We don't need 3 empty deserts. The main story should be the main reason that bring us to these worlds and makes us explore them. Add a meaningful side story to each of the worlds along with some in depth sidequests that actually have dialogue and choices.
3. More focus on companions: More personal sidequests (and not just one quest that lasts 10 minutes plus some kill/fetch quest), more involvement in the main story and a proper introduction (like Dorian if you side with the mages and Cole if you side with the templars) instead of a 3 minute encounter where they go "hey, I wanna be a part of your thing because reasons", more reactions when doing quests and while exploring the worlds, more interactive banter (we should be able to develop relationships while exploring too and not just at the base camp), make them wander around the base instead of being static in one place, I want them to initiate conversations with me (like sometimes with Hawke where you had characters visiting you). I want that sense of a real close group back. Also, more female companions (a female qunari? Yes, please.) as well as animal companions. A dog or a wolf you can save on some sidequest and/or a ranger ability where you can summon animals. And please, no more than 9 companions (even though I feel like 9 is already a bit too much).
4. NPCs that aren't cardboard cutouts and worlds with more life: I couldn't care less about Inquisition's NPCs because they just don't seem like people to me. They just stand there like cold statues. If you try to go past them, you can't, it's like trying to go through a wall. Make them react to what happens around them. If you start a fight, I want them to run or actually join in to either fight with you or against you, depending on the scenario. Also, more children playing and running around as well as animals like chickens, cats and dogs. If you can't give us a big village or a busy city, make them small but at least give them some life!
5. More showing, less telling: I don't want to be told that I have an impact on the world, I want to see it. I don't want to hear something big happened on the sidelines, I want to witness it. I don't want to read a bunch of codex to get to know the place I'm in, I want to experience it.
6. A more personal story. No more gathering armies. Origins was great. Inquisition not so great because we never really see that big army and allies at the end, but I think it's time for something new, yes? I think we really need a more low-key story after DAI. I don't mind being part of a group as long as it's a small group. Also, don't make the PC a hero from the very start. If they need to be labelled as a hero, let it be gradually like Hawke, or at the end, like the warden.
7. A villain that feels like a threat. I want the villain to actually scare the crap out of me. I want them to react when I mess up their plans. I want them to go personal and go after my PC's friends/family. If everything is all sunshine and rainbows it's just boring.
8. Better combat: Give us the ability to run with our weapons drawn and to change weapons during combat. Auto-attack. Freaking tactics! More abilities slots. Less flashy and shiny effects that can blind a person. "hold position" that actually works! A tactical camera that allows us to see past ceilings, has edge scrolling, that doesn't bump into every single object and doesn't get stuck in walls, cliffs, etc. Class diversity, like a dual wielding warrior that can also pick up a bow if they want, or a mage that can use a sword.
9. Better spells for mages. I was never a fan of the elemental spells, but they are so damn boring in DAI. And the worst part is that we ONLY have elemental spells, along with one specialization. It took all the fun of playing as a mage for me. There are a few elemental spells that I liked in past games, like firestorm or fireball, but alas, none of those were in DAI. We should be able to have a healing mage in the party if we want. It's always been there, it doesn't make any sense to remove them just because you want to force ~challenge~ on us. Also, mages really need the ability to walk while auto-attacking, like archers.
10. Better sidequests with proper NPC interaction, choices and cutscenes: For the love of God, drop the 3rd person view type of conversation. I don't mind it for simple fetch quests like Chanter's board, but keep those at a minimum and give us sidequests and encounters with cutscenes that allows us to actually see the NPC's faces and their reactions. I want to actually give a crap about them but I can't if they just stand there with the same expression on their faces while doing some weird gestures that don't match to what they are saying. And like I said, sidequests that have an actual story and choices with different outcomes. Which brings the next point:
11. Choices with actual consequences: If I don't gather supplies for the refugees, I want their opinion of me to change, I want some refugees to actually die of cold and maybe encounter a sad/angry family member later. I want to be able to screw up. Give us quests that have choices that affect something along the road. Maybe open different opportunities and/or close others. Which leads me to my next and final point:
12. Replay value! Not only for sidequests and main quests but also races. If you're going to include 4 races, I expect the game to be different in some ways, and not just a few different lines of dialogue. Give us some quests and choices that are exclusive to each race.
Retour en haut
. (Or, more probably, didn't have time to rebuild it for Frostbite, which is why I'm hopeful that it might return in the future.) The lack of fully customisable AI is the game's only really serious flaw from my point of view.
