Here's my short list of how to improve a Dragon Age game:
1. Replace the tons of in-game lore exposition (books, codex entries, dialogue, etc) with a short introductory movie about Andraste along the lines The Messenger.
2. Admit to yourself that you (Bioware) are, contrary to popular views, actually NOT good at writing, and retcon the Maker's punishment for corrupting the Golden City to include loss of speech. Implement most NPC dialogue as nods, head-shakes, hand gestures, and Brasilian Jui-Jitsu.
3. Admit that most players interested in tactical party based combat actually want to control the party combatants directly instead of assigning them tactical behavior routines and then watching Roseanne episodes during combat. Cancel said tactical routine development, use saved money to hire a philosopher to push the boundaries of Biowarean thought. It won't be easy, but one day, the mind can travel beyond 4 area hubs.
4. If implementing action combat, admit to yourself that you are clueless in this area, and after pretending to think of something, you will inevitably go back to Dark Souls combat. However, instead of simply adapting it, you will simplify it, and focus its entire essence on the act of rolling. You will have so much rolling in your game, those amateurs from Poland will look like stiff upright apes, and your menu sound-track will be the 90s Limp Bizkit song "Rollin'".
5. Stay away from obviously telegraphed villains. Of course the darkspawn archdemon looks somewhat evil, but perhaps you can disguise it in the comforting exterior of a mid-level bureaucrat. But definitely stay away from Loghaine-style emo colors. Here's an idea: have a really, really, REALLY annoying party member, some goody-too-shoes Paladin who is constantly getting on your nerves with his friendly yapping, and then it turns out HE is the villain.
6. If you have a really long and boring grind of a slog through some, oh I don't know, let's say dwarven caverns, have most of the spaces in them be Paid DLC content. That way, the discerning player can just follow the quickest free path the hell out of there.
7. If you must include a huge open world for no other reason that Skyrim sold a ton of copies, be sure to tie it to Steam Achievements. For example, separate the world into small regions, visiting each of which will give you a "Hey, look at this Skinner Box piece of cheese and enjoy walking through emptiness again!" achievement. Also, as Fallout 4 showed, an empty world can be offset to some degree by building mechanics stolen from other genres, so be sure to let the player build up a lot of stuff that has nothing to do with anything. Hell, build a dragon.
8. Learn from Bethesda, and a few months after the game's release, roll out an extensive game editor that can be used to mod the game to playability. Provide enough functionality to mod the combat, the world, the story, and if you are really feeling bold, to mod out the game itself for a different, better one.
9. Morrigan in DA:O had a really good voice. It was wasted on bickering with Alistaire and on pointing out all kinds of silly shit to the player, as if they had any control over it. Instead, direct the ire in that amazing voice on where it belongs, by having the companion with it incessantly insult Bioware and its design decisions the entire game.
10. Include the Exit Game option as a paid DLC, costing more than the main game and all the other DLCs combined. Have it presented to the player by a friendly NPC in their camp, who will also mention via a long dump lore that any attempt to leave the game bypassing the DLC will result in your PC's Entropic Death. Oh, how they will pay!