User blog comment:Arbington/New ME4 Teaser Pics, Possible Upcoming Reveal/@comment-1679409-20131114091848/@comment-1786741-20131115195035

Well, they do have to start from scratch from here in a sense. The game is probably going to be next gen with a completely new engine so they're only going to be able to re-use so many assets. Like I said in another post, they should take as long as they did with DA:I.