Here's the thing regular Battlefield games didn't even have single player campaigns. They were never about trying to tell a story, or make a statement, or anything like that. They were online multiplayer first person shooters were everyone got together and attempted to blow the crap out of each other with tanks and jets. It was never explained why the European Union was fighting the Chinese, who or what exactly the Middle East Coalition is, or why the Russians are fighting the Americans, because they didn't need to.
Even the Bad Company games didn't have anything like that. Bad Company 1's single player campaign was a character driven story about four misfit soldiers, done in the style of a buddy action comedy. You drove tanks on golf courses and flew gold plated helicopters through hostile territory. You didn't experience the harsh realities of war you did stuff like this.
I thought it worked very well. Not sure why they decided to deviate from that formula in Bad Company 2. I just hope if they ever make Bad Company 3 they retcon out all that nonsense about secret WWII EMP super weapons and South America.
tl:dr
You were expecting a deep and compelling story from a Battlefield game?