In my experience the problem of having many friend is not that the metter increase or anything like that... what happen is that because you have a lot of friends they are always login in and out all the time so every time a new friend is online the game load that info into your game screen and that can produce a little lag...
I always have 2 to 10 friends online coming in and out and I have 40 friends...now imagine having 800 friends you can have like 100 friends coming in and out. lol if you have the sound option on, you can go crazy!
May be a "hide friend list" option is not a bad idea... we can use it and when we re playing and we can turn it on in the lobby when we search for any game.