Next theoretical Mass Effect game

1) Have a good sense of the lore and history of the setting. This is vital for any narrative-heavy game. Particularly one that's set up to be a franchise.

2) Let players actually role-play their characters. This means letting the protagonist be carefree or stoic, happy, angry, sad, afraid, etc. And, yes, it means allowing the character to be an asshat sometimes as much as it lets them be a knight in shining armor. Heck some people even want to be the villain! Let them. I know it's a resource sink, but it allows greater replayability

3) Make tactics a thing. It was never a particularly strong feature in Mass Effect, but MEA was a travesty. We had virtually no control over our so-called "squadmates" At least let us equip them and command them when to use powers.

4) Worry less about setting up the next game (or book, or MP "story") and more about making THIS game as epic an experience as you can. No not in the "the fate of worlds rests in your hands" sense but in the "my choices shape the narrative" sense If choices matter, they should matter in this game. Ideally, I'd toss save imports out altogether and make every single game a standalone experience. But I suspect I won't be listened to in that regard.

5) related to 4: don't be afraid to create dark endings, IF the player's choice reflects that. While at the same time, don't be afraid to create happy golden endings, again, IF the player's choice reflects that. Don't lump everyone into a single type of ending, regardless of how they play. That is not respecting the player.

6) MOAR power buttons, please! Three is way too few. And the "profiles" system was a cr*ppy substitute.

7) The main story needs to be well thought-out. When all is said and done, we should be able to sit back and know how the pieces all fit together. Villainous motivations should be understandable (unless for some reason they are supposed to be inexplicable, in which case, we should also be aware of that) If we travel into a potentially deadly area without weapons, there should be a logical reason for that. If some miraculous new tech suddenly appears, we should know WHY it's there, and why no one else has ever heard of it, or why it hasn't revolutionized society already. Things don't have to conform to our own RL rules, but the rules should be consistent with its own setting.