Well, the netcode has to handle more information, for example now we have destructable environment which BF2 didn't have. Plus the upload speed of many internet connections is still not much higher than 2004, but I hope they have no cap when you play on custom servers -
if you can play on them...
I also hope that the ability to mount your weapon will make it into the final version. I always seemed kind of odd, that you could prone behind a wall, look over it, but are unable to place your rifle on it...
A quick accessible knife is ok in my book, in real life you draw a knife much faster than it takes to switch from a machine gun to a sidearm.