Have you looked at the effects of Critical Attack Power and Critical Rate in your parses? I've seen Kaeko's crit testing, but I believe the game has changed since then in regard to how crits work. Biggest issue for me right now is judging Crit gear versus STR/PIE/Atk.
I suppose the simplest test is how Crit Rate+ gear enhances crit rate. I've never seen numbers for this. Would be great to know.