Short answer: We have no reason to think so — but maybe?
Longer answer: A couple of days ago, gaming sites began reporting in a flurry about the possibility of Mass Effect 4 being teased at E3 2015, following an enigmatic tweet by Gamble which showed a Mass Effect-like horizon. In fact, the picture was from NASA and Gamble was merely being cruel.
But until Gamble revealed that fact, rumors spread like wildfire — the most dominant of which was that a trailer, release date or other announcement regarding Mass Effect 4 would be revealed at E3. These rumors are unsubstantiated, based on a tweet that was a joke.
Once again we see how a news cycle doesn’t need to be 24 hours, but it still needs to be more than 24 seconds.
Okay, but — Mass Effect was released in 2007, Mass Effect 2 was released in 2010 and Mass Effect 3 was released in 2012. For Mass Effect 3, the first trailer was shown in 2010, two years before its release. Mass Effect 4 is clearly not coming out in 2015, but 2016 is not entirely unlikely.
It would actually be very strange if we don’t get a Mass Effect 4 trailer soon, and E3 2015 would be the perfect place for it. In fact, if there is nothing announced at E3 2015, it’s safe to assume that ME4 won’t be out until 2017. So it’s not unlikely that Bioware may tease ME4 at E3 — especially given the recent leaks — people are simply believing it for the wrong reason.