The way they talked about vehicles in the MP suggested that they may add them in at a later date via DLC. They just didn't want to put them in now since it would introduce too many variables and they don't want to mess up the flow of warzone. The ONLY thing I'm honestly hoping they work on more is the recoil of the guns. It just looks way to easy when they're playing like they'll be in CQC ADS at an enemy. I hardly seen any hipfiring.The single player gameplay did remind me of Halo a lil bit, but... nah to vehicles, I don't want them in Killzone and the 1 time they put some in there (with the mechs in KZ3) the multiplayer wasn't the same and they were too hard to take out.
Leave the vehicles to Battlefield.