I don't think BF3 takes more skill than COD, I just think BF3 has more going on.
Everyone who plays games seriously can drive vehicles in BF3, shoot and kill, and play well enough to score in games. It's just a matter of how much time you spend with the game learning all the little things, same with COD though, some can get 25+ kills a game easily with few deaths, where as others get more deaths than kills on a consistent basis.
It's all about time spent learning the mechanics.
“Anna, my strong, terrifying Anna.” -Cas
"You lack the requisite spine and testicular fortitude to study under me" -Elodin