What are the differences between the Battlefield series and the Bad Company series?

Solution 1:

The destruction mechanics are different. In Bad Company 2 you could essentially level an entire map, which Dice now wants to avoid (don't know why, probably has to do with flow of battle) so only certain things are destructible in the latest Battlefield games.

Also classes worked differently. Support class did not exist. Medics were a separate class from assault and had the LMGs while assault had assault rifles, C4, and ammo packs. Recons also had C4 as well and the ability to call in mortars. Engineers got the rocket launchers.

Another thing is that the Bad Company series was a side project for the game developers while work on the new frostbite engine was being done. So it is essentially still a Battlefield game, but the developers had more freedom (as most of the team was busy with frostbite)