The problem with much of the above discussion is that it focuses on extremes--the either really terrible or really amazing "god" players. The middling players are left to the randomness applied by the PSR's team based weight.
I question a ranking system where I have to play like a god to regularly ascend, and any other match performance (above average, average, middling) is treated relatively randomly--my personal score is based entirely on my team unless I am so amazing I can counter the random abilities of 11 other players.
Inouye's own post references that the new system is built around team play, and actually encourages it--hence the focus on team W/L in the OP's posted graph.
The problem with this is PUGs are rarely team based, and if they exhibit any kind of team work, it's the most basic "rally point" or "enemy sighted" chat directions. So from what I can tell, the biggest problem with the new tiers is that they are heavily biased against PUGs. Anyone of middling skill (I average about 200-250 dmg per round, only play lights and meds) who plays PUGs is then forced to deal with the reality that their PSR is completely based on the randomness of the teams they are assigned.
Either PSR should be based on *your* match points (as the OP suggests) across the game, or there should be some changes made to differentiate between PUGs (where players are going to be more dependent on their individual skill level) and true team based play (where the current PSR system makes more sense).