XanYou are right. Butttt, I did try to take teamwork into consideration when I did the TEAM rankings. And also the pocket/medic rankings. Not so much the "top 5", which is pretty much why it is completely useless aside from getting people talking about something.
teamwork doesn't just come from teams playing together for a long time, it comes from some players who are more predisposed to working off their teammates, or frankly are just smarter or more dedicated to begin with
therefore it has to be factored into individual rankings for them to be accurate