In a recent blog post by BioWare Montreal studio director Yanick Roy, Roy revealed that the next Mass Effect game will be developed in the Frostbite engine, the same Electronic Arts proprietary engine used in a range of franchises, most notably Battlefield, Medal of Honor, Need for Speed, and the up coming Dragon Age III: Inquisition. Speculating with other news from Dragon Age III, this choice might have been heavily influenced on the fact that the Dragon Age development team has been hard at work adding new game mechanic systems to the Frostbite engine for their RPG. BioWare stated that Mass Effect 4 will be taking advantage of several of those new systems, but no specific system was specified.
Shifting to story and gameplay itself, Roy explained that the next Mass Effect game will be advancing in a new direction away from the previous games in the series, but that the next game will still be respectful of the history behind the first 3 games.
“You can still expect the pillars the franchise is known for to be fully intact though, including diverse alien races, a huge galaxy to explore, and of course rich, cinematic storytelling.” -Yanick Roy, Studio Director at BioWare Montreal
Unfortunately in the blog post, Roy said it is “probably going to be quite a while before you hear from us again.” BioWare has yet to release details of how far along the game is in development, and there has been no solid hint to any kind of release schedule either.
Source: Blog Post [French]