I have only had a couple incidents on consoles. it's much worse on PC for me. I can't even use my microphone because someone will give me a hard time. people use aim bots and speed hack all the time
You use BF3 as an example, but with 550 hours into BC2, I feel I have a pretty good amount of seat time to make a judgement on hacking in the BF games, and I have seen very little. As far as mic's, I hate open mic's so I just turn them off. Either way, small maps and hacking is going to be worse, the larger it gets, the less head shot scripts are going to matter, you can't head shot a guy out of a tank. And larger maps will involve more vehicles, any hacker I see playing BC2 plays Arica Conquest, or any other map with no vehicles.