I have a better question: Why are you making Mass Effect 4?
This isn't a question that comes from my deep-seated dislike of the ending of Mass Effect 3. I happily admit that I don't like the ending, but that's not why the question of whether the game should be a prequel or sequel disgusts me. This is a horrible question because it demonstrates unequivocally that there is no vision clear vision for Mass Effect 4. It tells me beyond all doubt that Mass Effect 4 should not be made, or at the very least, it should not be made with Casey Hudson at the helm.
Asking fans for ideas of the setting in this way indicates that either Casey Hudson and whomever else was involved in green-lighting this project does not have a vision for the game except that it must be "Mass Effect 4". This is a clear indication that the only reason that it is a Mass Effect game is because it is a bankable IP that has sold millions of copies previously. That's it. All I can say is: Shame on you.
I have possession of the intellectual property!
You might think I'm being a bit harsh on Casey Hudson here, but he is ultimately in charge of the IP. The buck stops with him, which means he has to own it, and if he doesn't have the vision of what the next game in the series should be, then he needs to hand the reigns to someone who does. If he's not doing that, then he's not doing his job properly, nor is he treating the series, its fans, or the IP itself with respect.
The reason this question is particularly abhorrent because if there is one thing that gamers and the gaming industry as a whole has a surplus of, it is ideas. The industry is filled with creative people and more ideas than could ever possibly turned into shippable games. To have to ask fans "what game should we make" indicates that the people behind the project don't have that vision and don't have a clear picture of what they want to do except to make a game that is part of a franchise.
This is kind the of attitude that gives us the stale churn of titles over and over again, what allows companies to get away with just delivering the same old formula just to get sales. To do this in any genre demonstrates a lack of imagination, but do it in the RPG genre in which storytelling is such a core element of the experience is a travesty for existing Mass Effect titles as well as the RPG genre as a whole.
What do you mean you don't have a story?
I understand that the content of a new Mass Effect game might be a touchy subject given the backlash against the ending of Mass Effect 3, but trying to make another game without a clear vision and strong idea of what game you want to make and why is only going to result in the production of an inferior and soulless product. If there was ever a way to attempt to repeat a backlash on par with that produced by Mass Effect 3, this would be how to start it.
I could make a whole post about the delicate balance between balancing what gamers want and how much the developers should stick to their core vision. While Mass Effect 3 arguably pushed the boundary too far in the latter direction (though many applaud it for doing so), relying on the audience even decide the core setting or the story swings the pendulum far too much in the other direction.
If you don't have a vision, don't make the game. Gamers deserve better, games deserve better, and developers deserve better.