MP is great. And the campaign isn't bad. It's an actually good campaign which lacks some real highlights but only has one real downside, the team AI. That doesn't matter on normal, but it sucks if you play on legendary.
Final issue, splitscreen. Just finished Halo CE with my daughter, though we're only playing once in a while. So we'll probably need months until we're done with all splitscreen campaigns. With Halo 5 we can't.
No splitscreen actually is a standard today. But having splitscreen that usually worked great was a Halo standard.