"We have already said that the Commander Shepard trilogy is over and that the next game will not feature him/her. That is the only detail you have on the game," explained Priestly. "I see people saying "well, they'll have to pick a canon ending". No, because the game does not have to come after. Or before. Or off to the side. Or with characters you know. Or yaddayaddayadda. Wherever, whenever, whoever, etc will all be revealed years down the road when we actually start talking about it."
Priestly went on to clarify that he doesn't call the next game Mass Effect 4 because it makes people think of what happens after Mass Effect 3 rather than what game happens next in the Mass Effect universe, "which is far more accurate at this point."
"Obviously fans are going to speculate content, character and story until we actually reveal details in the years or months to come as you have almost no actual details, just don't get bogged down in "well how are they going to continue ME3..."," he concluded.
And this, my dear readers, is why you should use subtitles with your video game titles. As the Mass Effect series clearly proves, a simple incremental numbering system doesn't work because it doesn't allow for the idea of a prequel, which is something that has been tossed around for the premise of the next game. It's sort of like Star Wars. If A New Hope was simply titled "Episode 1" when it was released, then imagine the confusion when Lucasfilm went back and created the prequel, Star Wars Episode 1: The Phantom Menace.
As for me, I'll still be referring to it as Mass Effect 4. Can't teach an old dog new tricks.