Tomb Raider 2013 had a good cover system, Lara just naturally hid behind cover during firefights if you were close enough and it never felt sticky.
Those games... well the first two, haven't played Shadow yet... also benefited from their combat rewarding movement a lot despite having a cover system. Also a heavy helping of stealth. I felt like a constantly moving predator in those games, while in Mafia 2 I felt like a stationary gun turret.