i know its too early but recent announcement from Bioware's Aaryn Flynn during Doctors Ray Muzyka and Greg Zeschuk retirement, pretty much confirms that Casey Hudson and the team are starting to work on the next full game of the Mass Effect Series.
" • MASS EFFECT – Executive Producer Casey Hudson and his team are coming off an amazing eight-year run with the Mass Effect trilogy. But they’re not done yet. We are releasing more multiplayer content and we have more single-player stories coming throughout the next six months, including Omega which is coming in the Fall. But the Mass Effect universe is vast, and Casey and our teams have plans for another full game. “Where to go next?” with such a project has been a question a lot of us have been asking, and we’d all love to hear your ideas.
• BRAND NEW GAMES FROM BIOWARE – Both Dragon Age and Mass Effect started as single games but grew into vast universes. But we aren’t stopping there. While Casey continues to oversee the development of our new Mass Effect project, he and his leads are putting together their vision for an all new game set in a fictional universe, built from the bottom-up with all new gaming technology. " - Aaryn Flynn { From Aaryn Flynn | BioWare Blog }