I have never been one for playing game online with others I have tried the COD and other first person shooters as well as the Assassins creed multiplayer, and to me it just was not as enjoyable as playing through the story and any side missions but that is just me.
So for me i would like to have an option for disabling multiplayer achievements, I am not for having them removed from game as there are plenty of people who enjoy the online aspect of the achievements. I would not mind at all if they had it separated where to show offline stats vs online states. Even with the PS3's trophies system, I would like to have them at least separated so that one could platinum through offline play as well as still be able to get any online trophies if they so desire.
I guess my standing would have to be make Online achievements / trophies optional.