I think this a great idea for tracking PR value, it would have helped me a lot along my Splinterlands journey. The charts themselves are a bit of a mess, with too much data overlapping. I think pulling only a handful of examples (like the top, bottom and a middle example) or registering the charts different would make them a lot easier to visually digest. I do enjoy your work though, keep it up.
RE: A new? Metric for the card market