Very good news update! - SPOILERS
So when Brother Day was murdered in the season 3 finale, one thing makes it clear Lee Pace will return: Brother Dawn is still alive and in a decade (show time) or so he will grow into a Brother Day (Pace) lookalike!
Another interesting point I read that I missed watching the show: Demerzel's eye flashed morse code right before her skull blinked out. No bullshit, it said "Transferred."
Makes sense since Lee Pace and Laura Birn are the biggest stars of the show. Apple would be nuts to eliminate their two biggest viewer draws. These two are the money makers for the show.
Reports are already out that Pace and Birn are signed for season 4.