Due to time constraints, the studio had to scrap its support for Spectator Mode, Theater Mode, nor even a skill-matching system like the one seen in Halo 4—not that it works very well. Crytek has no plans to implement co-op mode, either, as the focus in C3MP is mainly on competitive battles.

The Power Struggle mode, previously available in C2MP, will not make a return in Crysis 3. However, he added that the studio has an unannounced game mode which will be revealed upon the game's release.

Time constraints guys. I don't many of us would have minded that much if they pushed back release so they had enough time to implement some of these features.
http://www.gameranx.com/updates/id/12825/article/crysis-3-multiplayer-info-blowout-modes-maps-weapons-admin-privileges-detailed/