Assault Game modes.
How about implementing a Timed Game Mode where the Objective Point's change uring the Game where you have to land on a Beach and fight yourself inwards of the map. Once you have captured the first objective the spawn point and the Capture points change and the conflict Escalates.
Imagine starting the Game of beach assault with only the infantry and Logistics, Recon and AA Tab Unlocked, the Attacking force Captures the first Point and now Helicopter, and Tank tab gets unlocked and on the 3rd Capture Arty and Planes get unlocked, the 4th capture then is simply all out war with evrything unlocked and evryone trying to win. Evry stage of capture should be timed to like half an hour or so and once a Point has been captured the Timer resets.
I am aware that Maps have to be Speciffically made or changed up for this Gamemode.