Um, no way... Simply because it's a waste of the programmers'/webmasters' time.
All that will happen is people will grab a friend, and then they'll just kill each other over and over just to get to the top of the list. This WILL happen and it renders the ranking system useless.
It's way too easy to be lame in PvP (not really FC's fault. There's not much they can do about it), so this would just be dumb. Spend some time on something that a majority of people want you to do (such as, ANYTHING ELSE **IN-GAME**. NEWSFLASH: WE DON'T CARE ABOUT THE WEBSITE), not something that people are split on.