I'm not sure if there are any devs actually reading this, but first off: thanks
for an amazing series so far.
I agree with some other posters that the constant fan "disappointment" exists largely
because you take fans seriously and listen to
suggestions. However when someone doesn't get something specific they asked
for they get upset. I'm sure you're already getting a lot of "betrayed" fans asking why you didn't show Tali's face in the new citadel dlc.
I think it's awesome that you consider fan ideas in a sort of brainstorming capacity though so here's my two cents.
-I agree that the storyline of the
next ME
game needs to be more personal and less "fate of the galaxy"
-I agree that the environments need to feel large. The ME1 universe seemed so expansive and free b/c of this.
-I think a prequel would be cool, however I'd like to see more Krogan, Quarian, etc. I think going all the way back to prothean empire might be a mistake. While it would give you more freedom to create a new universe with new species, I think you'll lose some of the connection to the Mass Effect universe as we know it. You've got plenty of material
for a prequel set in this cycle (Morning war, Rachni war, First contact, etc.) I'm not sure what the timeline of the galaxy's history is but some of those may be able to overlap. (e.g. does the morning war have a set date in galactic history? Is it possible that the Rachni war could be simultaneous?)
- The key I think though, wherever and whenever the
game is set, is that
your character is not commander shephard: singular important hero in a galactic war.
Your character needs to be more of a
Forrest Gump in so far as s/he has a storyline that causes her/him to find herself/himself in the middle of historic events but without actually being "important." Think of how
Forrest Gump witnesses the watergate scandal, fights in the vietnam war, brushes up with the hippy movement through his girlfriend jenny, etc. He's really a nobody but he witnesses firsthand the defining elements of a generation. (Obviously lose the Candide-esque simpleton's optimism of Gump though, lol)
-I'd like to see more science fiction than science fantasy, and I'd like to see more RPG than fps-ish polished gunfighting, but that's just personal taste. I do think detailed codex entries, planet in
formation, etc. helps with the "bigness" of the universe though. I really enjoyed ME1 when you talk with the elcor and get a sense of how they're culture developed based on the environment of their homeworld
for example. I liked the more sci-fi-ish explanation of biotics offered in ME1: a person's nervous system is electrical in nature and can there
fore manipulate mass effect fields after exposure to eezo, but this is a weak electrical signal that needs to be amplified. Even the biotic attacks reflected the mass effect
for which the series is titled. Lift obviously lowered the mass of a target, warp seems to be some sort of spatially and temporally oscilatting mass effect field that causes particles' masses to fluctuate which would clearly do some messed up stuff to
your body. By ME3 you have biotic charge and lash and dominate: clearly just space magic. Enter science fantasy. The point of this whole rant is that a science fiction series feels "big" and is explorable. Star trek vs. star wars is a perfect example of this: star trek episodes explore different ideas and concepts in a massive universe, they highlight human nature and ethics in so doing. ME1 did a great job at this: What if there was a hivemind species? --> explore Rachni, should we kill the queen? Let's explore the possible outcomes of an AI--> Geth/Quarian conflict. Star wars introduces a hero's journey and relies on action/adventure and victory over dark
forces. I think the science fantasy route fit commander Shephard towards the end of the series, but now that is done and we want to do some more exploring and customization of our character. The "choices" mechanic works a lot better in a sci-fi world as well. In a science fantasy world the choices are kind of simple and not as fun: you end up with "light side of the
force or dark side" "Paragon/Renegade" and the choices lose some subtlety. Saving/Destroying maelon's data was a good example of a subtle/difficult choice. These scenarios become less interesting and less common in a galaxy unified in their warfare against one, big, bad guy.
-So in short: I think the best parts of the series were: the peronal relationships and the complex galaxy you created. The genophage, the quarian/geth conflict, etc. These are great ethical environments to unleash the choice mechanic onto. Do what you do best and give us more interesting choices, and give us more loveable characters! The way to do that is to not put
yourself in a position where the entire galaxy is at stake.
Thanks if anyone actually read all that

tl;dr- go more sci-fi that sci-fantasy because you get a bigger feel and more interesting ethical choices
- don't put the galaxy on the line because you lose freedom in writing that way.