Sleep well, Call of Duty, your contender didn't do its homework
First, there's a steep learning curve. This is not a multiplayer you can just pick up and start neutralizing your opponents. You have to experiment with the classes available, and find out what they do. You have to learn how to operate the vehicles available (you have to do it on the fly, as there is no training anywhere else in the game), and learn how to destroy them. You have to have a sense of what's the strategy to complete the objective and how to approach the enemy. In short, you won't feel comfortable at the start.
The screen layout is not as confusing as past Battlefields. Now its more clear to see when you kill an enemy or what's the score. Still, is not as clear as other FPS out there. The competition has a very rewarding leveling system that makes you feel accomplished for almost everything you do. In battlefield, leveling up is slow and it feels like upgrading anything takes forever. The classes have some confusing options (med kits on assault?) and in 2011, you still can't create custom classes.
The extensive maps make the pace of the battles slow. You'll spend more time running than gunning. The spawning system helps this a bit, and focuses the game on teamwork, still the action should have a more even pace.
On top of this, add an uninspired campaign mode. You'll almost fall asleep at your controller playing what it looks like a rehash of the flashback story of CoD Black Ops.
I believe Battlefield has many points on its favor. The guns feel and sound amazing. The graphics -even when not as good as the PC graphics- are top-notch. The technical aspect is completely polished, it's the gameplay aspect that needs a little work.