I think that the way their developments cycles work in conjunction with their marketing, I wouldn't expect to see the new mass effect game until early 2016.
I guess that's a possibility as well. Then again, we've been told that this game was halfway through development months ago. While the game started development shortly after the release of ME3, let's assume that development started in late 2012 (after Bioware Montreal finished the Omega DLC, when they really had a chance to start full work on ME Next). We get this:
November 2012: Beginning of ME Next development
April 2014: Halfway through development tweet
November 2015: Release of ME Next (Hypothetical)
That's about 16 months. Double that and we get 32. Round it off to 36 and we have a 3 year development cycle. With a 3 year development cycle, we get a release date of Fall 2015
Considering that DAI will have close to 3 years of real and full on development (It was announced on September 2012, but DLC stopped in March 2012, so that's the real beginning of development), we get this:
March 2012: Beginning of DAI development
November 2014: Release of DAI
That's about 32 months of development. If you want, you can even bump it to 36 months, for preliminary/brainstorming work.
My point is that according to all the info we've gotten:
1) DAI took longer because the Dragon Age team was the sacrificial team for the next-gen. This involves tech stuff, like frostbite
2) ME Devs have said their dev cycle would be decreased thanks to the efforts of the Dragon Age team. The engine is now optimized for Bioware RPGs, so stuff like dialogue wheels and RPG systems are already coded at their base
Basically, ME Next should have a shorter development cycle than DAI. As such, the game would not release in 2016 unless the team needed to expand the scope of the game like the DA team needed. ME Next in 2015 is most definitely a likely possibility.
Besides, as much as I hate to admit it, having a space opera blockbuster like Mass Effect, amongst the first big space/rpg games for the next gen, to release in the holiday season would be nothing but $$$ to the eyes of EA.
I wish Bioware takes all the time they need to make an incredible game, but based on what we know, it cannot be as far out as some estimates have lead us to believe.