I personally would like to see an option due to my step mom doesn't want to have her kids hear strong language and my lil broski always wants to watch me play. I think if they put the option in they should not bleep it out but rather replace the words with random names of fruit
http://www.youtube.com/watch?v=yWoI-1qWT4Y
Way better imo. Anyway, on-topic:
I honestly think swearing has its merit in games for immersion (i.e. BF:BC2 U.S. troops shouting swears at Russians, especially for Avenger kills), just don't make it sound like I'm sitting in a high school lunchroom or listening to [c]rap music.
However, if swearing isn't included, I certainly won't refuse to buy the game because of it, but I do think a lack of it would slightly detract from the atmosphere of cops fighting terrorists or freedom fighters fighting oppressors (depending on your point of view), as I'd expect at least one or two "[censored] YOU [censored]"'s from a situation like that.