"Realistically, for Halo 5, it's not something we can just throw in a patch," O'Connor said. "It's just not feasible with the way the engine works." Now, before you get too sad, O'Connor admitted that the blowback to splitscreen removal has been "huge," and that just because it's not in Halo 5 doesn't mean the feature is gone forever.
"Splitscreen is fun for me too. It's not something that I object to, and we would've loved to put it in," O'Connor said. "We'll talk about it for the next game, and we'll talk about it for the future."
http://www.gamesradar.com/halo-5-doesnt-have-splitscreen-halo-6-might/
Saw the other interview from Gamesradar posted, but didn't see this one. Compare me to Star Wars if old