Mass Effect 4 is one of the most anticipated role-playing games but we know almost nothing about it. We don't even know the game's title yet. We're just calling it ME4 for lack of a better working title.
Maybe the only confirmed detail we have about Mass Effect 4's story is that it won't star Commander Shepard. Beyond that, we don't have a clue how BioWare will continue the series. They've got an entire galaxy and millions of years of history to draw on for the next game.
Here are a few different ideas that BioWare could use for Mass Effect 4 and beyond. None of them are perfect but each could make a great RPG.
The idea: The Reapers have wiped out all organic life in the Milky Way Galaxy many times over before the events of the Mass Effect trilogy. BioWare could craft a new game around one of these previous cycles. The main character would be a member of some long-forgotten race trying to stop the Reapers' genocide - and ultimately failing.
Why it would work: Setting Mass Effect 4 before the dawn of mankind gives BioWare a nearly blank slate. They can create an entirely new set of alien races and characters for this earlier era. This time period also enables them to keep using the Reapers, a memorable and fearsome set of villains.
Why it wouldn't work: A blank slate is a double-edged sword. Creating a game before mankind or most Mass Effect races exists means that the game will have only minimal connections to the rest of the series. Why make a Mass Effect game that makes little use of the thousands of years of established lore built up from games, comic books and novels?