Taking a look at the other bp's that drop off the various Avatar's of "so & so", I can't see any stats that grant + to Base CA, only +CA. perhaps I am looking at the wrong information. The only BASE amount I can see if the BASE TAUNT amount.
Looking at the Wu's again, there are some added +10 agression, +15 deflection. Again these aren't found on other bps that are similar, so these could possibly limit the amount of critical mitigation on this piece from a developers point of view. I know that none of these are exactly the same as having the full +40 crit mitigation as the other bp's, but having a lower crit mitigation could be justified.