I see more bad reasons than good here. For one, some people on here are either friends with hundreds. How would that person get all them onto a friends list?? Maybe put a few in, but then to the others it wold be like saying "You're out of my 5" (

). Some of the "gamers" on here will definitely use it to 'spy' on other countries. The biggest frustration that could come out of it is those few who would be sending friend requests to EVERYONE! Sure you can just set the message to the text bar and not a pop-up (like we do with the join requests), but I for one would be quite annoyed seeing a guy, whom I don't even know, sending tons of friend requests to me! Would really spam the message bar!
To keep this from being all negative, the fun things would be knowing if your "BFF's" are on and where. Always fun to play with some great friends.
