The only one complaint I've had about the whole game is the lack of an EXIT command from the main menu on the X-Box 360 version. You have to mash the big X button on your controller and push the yellow Y button to force the game to close and get back to the Dashboard.
what other games have this ability? Only time I have seen this is on Demos . . .
The difference between campaign and free play is on campaign you get the story and go through the levels in order, you don't pregress unless you are on the winning side. Free Play has a Vote Next Map option at the end of each round.
Also for some reason the Stats site doesn't track your stats on campaign, only free play, what a jip!!
As for the unlocks, they can't really change that now, would be seen as "unfair" to newer players making it more difficult to opbtain items the rest of us got so easily, also lets say a level 10 has unlocked everything, they could't take something off that character that they have already unlocked just because they changed the rules.
On the topic of lobbies, I'd be happy to just have a place whre I can group my friends together before we start and we all join the same game at the same time (BC2 Style), the perfect way would be the same as Halo or CoD party/lobby system.