I hope they include a fire mode selector for every weapon.
Many people don't see the importance in this, stating that you could just click the mouse button quickly for single shots. While this is true, it's not the most elegant solution, especially for high rpm weapons. I also think it promotes steady shooting and accuracy, over weapon spamming (spray & pray) as is clearly evidenced by the gameplay in BC2.
Also, the ability to lean would be nice too.
I like the fact that there is NO fire selector in BFBC2. It means that I'm the winner of most firefights over a longer distance if the other shooter isn't capable of firing single shots. And you can train yourself to fire single shots every time.