The design decisions we've always disagreed on. The features (Theater, Firefight, etc) I really do think can be attributed to time issues. I don't think this development went smoothly. I think they may have tried to implement Firefight but struggled with it, and couldn't afford to spend more time on it if they wanted to ship, so they cut it. Same with a lot of missing features. Makes sense when you think about how they came out upon launch and said "we are really looking at adding full features in through patches, not just fixes."
There was an executive decision made somewhere that Firefight, campaign theater, scoring, etc. would be cut, and I really can't see that it would have been "just because." If it was cut "just because" then I'm in the wrong but something tells me there is a LOT more to the story of Halo 4 development than we'll ever know. I just hope they can get these features back in, and get the core gameplay issues/balancing fixed.
I honestly hate how a lot of people seem to think all 343 had to do was "copy and paste" features over. If that was all they had to do we'd see those features. Something happened to get them cut.