I voted for Bad Company 2, because it's the right answer, but I just want to take a moment to give Hardline a little bit of love.
If you went into Hardline looking to play Conquest-mode, you would have been disappointed. The decreased emphasis on armor, aircraft and heavy weapons made that a bit of a non-starter, and fans were understandably not supportive. However, if you were willing to try out ANY of the new game modes, you were in for a fucking treat. Domination mode with mobile control points you need to blow up? Fuckin' Hotwire baby! Want to try and assassinate a target with a small team? Mother fucker we've got that! Hostage rescue? Got that too! MOTHER FUCKING HEISTS? HELL YEAH MOTHER FUCKER!!! Seriously, Hotwire and Bank Heist matches were some of the most fun I have had in a BF game since BC2. Riding shotgun with a grenade launcher taking pot-shots at an tanker truck, setting up roadblocks and lacing the ground with C4, weaving between buildings with a helicopter and raining death on the cars below, taking a zipline to an extraction zone and the ensuing fire fight as you wait for the helicopter to come. It was just very focused an intense and I loved every second of it.