User blog comment:James12708/Possibility of a Mass Effect 4/@comment-2250460-20121028163027/@comment-5267262-20121028170614

I agree time is an issue, at one interview bioware did (Idk which so I wont be able to find a link sorry). They estimates that they had from tens of thousands to millions of possible save states that someone's trilogy could be at. Some of these are obviously going to be the same track at different points but thats still a whole load of configurations to sort out. Something that picks up on the major choices (genophage cure, rachni and geth saved etc) would take a while. But having missions or conversations that rely on so many other things (like conrad verner in ME3) would take at least half a decade to do adequately. Sadly if duke nukem has told us anything about games with a long development times: they aren't worth it.