I don't really see the need. It's only a very minor improvement, if you can even call it that, and as someone else has stated previously, it can mean fights may break out. I don't see the problem. What happens if you have more friends than are able to be added to the 'Top Friends'? And more importantly, they are all your friends. If you can put places on friendship, then I don't think that's very fair. Sure, you'll have your 'best' friend, but I still think it's wrong to have some over others.
~T_S