Nono that's the point of assimilation: the people with the highest scores would have the largest negative impact on your network, were they to fall away. If one of the friends that you share a lot of friends with were to unfriend you, you'd hardly notice because you share so many friends in common. So by that metric they're not that valuable to you.The two people I communicate with most on facebook were well near the bottom and they shared a ridiculous amount of friends and interests with me.
Okay, well let me add this new datapoint, my first highest on the list was my brother. Who I went to highschool with and have the same friends. I don't see how he ranks differently from other friends... I don't know. The whole thing is just kind of weird.