No matter how much you try to keep things balanced, it can never be archieved, we already had a thread about that.
MouRO also had that problem, and it is still unsolved. It is way better use the Scissors Beat Paper that beat Stone kind of balance.
Back on track to crit, what would I change it... Make it bypass phen, make it bypass endure, if your weapon have a status inflicting card, it effect to apply is doubled when you crit, and uh, even if OMG LOL OP, every crit has a chance to inflict the same statuses as Joint Beat.
Well, this is what I would do if I owned a server.
Also, I guess you mean every 5 enemy luck, he get 1 PDodge, and 1Pdodge = -1 to get critically hit, well, that would mean that people would have to invest some stats in luck to avoid getting too critied. Maybe you could make PDodge like a Crit only reducement, for example, ever 5 luck, you receive 1% less damage on a crit. Don't be afraid to test out other meanings to fix crit, you can add them on skills, as WoW do, or make them as I said above, it might look overpowered, but since you will have to fight agaisn't someone without burst, it WILL take time, which mean, enough time for them to do anything, from potting, to backslide/running.