I hope they change/add more voice-overs and make them good, some were really good in BO2 - this adds to the immersion so much.
This.
For Multiplayer
Modern Warfare - 4 factions.
World at War - 4 factions.
Modern Warfare 2 - 6 factions.
Black Ops - 6 factions.
Modern Warfare 3 - 7 factions.
Black Ops 2 - 6 factions.
Ghosts - 2 factions.
Advanced Warfare - 2 factions. (Even though in the campaign, there were a lot more factions involved like the Nigerian Armed Forces, Korean People's Army, KVA, United States Army and Police.)
Honestly in multiplayer, I am getting tired of hearing the same 2 announcers over and over again, since Ghosts. I really hope BO3 sticks with 6 factions or more and have a variety of announcers. Also, the announcers should show some encouragement, enthusiasm and fear in their voice, when announcing Scorestreaks. I feel like this is what Call of Duty is currently lacking in the sound department. Immersion is key in Multiplayer.