Vehicles are Battlefield for me. It was was one of the key factors that distinguished it from the COD series, imo.
What they managed to get right for the majority of the series has been the rock/scissors/paper aspect of using vehicles. They can be a game changer for the team - or a total liability if not used properly. I recall one of the biggest rage inducers of BF2142 was in Titan Mode where someone would nab the transport from the Titan's hanger - nose-dive over to the nearest capture point and simply bail out, letting the transport crash to the ground. In the meantime, several other players were sat around on the Titan deck, awaiting for the written-off transport to respawn.
If they had waited approx 5 to 10 seconds, they could load up with seven players (including the pilot) and make a bee-line to the nearest capture point - allowing a full squad to capture and defend the point, rather than a lone Rambo. That said - an airborne transport with seven players in it, makes for a VERY tasty aerial target. Again - that balance of risk and reward - dependant upon who was playing at the time.