For me, it's Bad Company 2

BFBC2 had the perfect formula for a BF game

Each gun had a distinct feel to them. Sound was amazing and there was only heli's and no jets. As much as I love jets, it really unbalanced the game because it requires you to have a massive fly zone to fly in the map which fucks with balance

Don't know about that but this is where the Battlefield franchise peaked.