The titan mode from battlefield 2142 might be coming back to Battlefield 4 in one of the upcoming dlc. The titan mode was very popular for BF2142 in 2006.
Gustavsson was asked about a titan mode in Battlefield 4 and he said that it was on the list of ideas and that they have not really decided for the content in the future expansion packs for Battlefield 4.
There are 5 expansion packs scheduled for Battlefield 4. China Rising is already out with Second Assault on the way. My gues would be that the titan mode will be coming in the final stand dlc for Battlefield 4 because of the name. Naval strike would also be perfect for a titan mode.
Titan Mode Explained
In the titan mode two teams each control a huge flying aircraft carrier know as a titan. The titan aircraft carrier can be shot from the ground with missle sites which depletes their shield. The more control points each team has the more missiles can be shot at the titan. Players can take over the enemy titan when the shields are down and destroy the inner core which will win you the match.