I would personally like to see facebook go down. I don't really think it would be all that great if Google was the one to take over, because they seem to be taking over everything these days. It would be nice to have everything in the same place.
I don't think it would work. User are so tightly involved with Facebook that the transition to Google would require EVERYONE on your friends list to transfer (else it becomes a pain to use two different websites). So.......highly unlikely. Currently, there is no specific reason for people to jump em masse from FB to Google.
If they leave out ties to stupid games and quiz crap I'm all for it. Facebook essentially became the new myspace, not so much because of the games and quizes, because it inherited much of the original myspace user base. With that came the myspace mentality. Before I joined facebook I didn't know how emo a lot of my friends were.
Facebook is fine, I don't know why you people think it's so bad. They fixed the privacy settings, what else is wrong with it? Nothing. Way better than that crap a couple years ago called Myspace. Everybody I know uses Facebook and I'm fine with it staying that way.
Google will have to be much more careful about security than Facebook has been. Their reputation being damaged would be a huge blow and probably not worth the social network traffic. They'll have to think long and hard about the mistakes that Facebook has made before taking the plunge.