A counter-based Avoidance Tank is very nice. I like your class overall but it needs some adjusting.

A few notes though:
-I would like to know more about the Counter-Stances that some of the skills give. How long do they last? Are they like a buff? Are they the same or does each attack have a different stance that can add to the others? Do stances reduce damage done?
- Mirror of Equality has a bit too much going on, it's a kind of like a Rampart with Second Wind built in that also attacks a foe for 250 potency and you get it at level 8! I get that you tried to balance it with the 20% HP limitation but then you're counting on the player to not have a healer there to cap them. It's either going to be too good or under used.
- Reverse Grip's Counter Stance stays up til the cooldown is done? That's an 120 seconds then just hitting the button again. That would make all the other ways to go into counter stance redundant then. >A>
- Purity Channeling, if I'm reading this correctly, turns an enemies attack into a DoT on the Ronin which can then be removed by a healer when they are in a counter stance? I don't mind the idea but the fact that it's cleanse-able is kind of broken. Also, how is the DoT's Potency determines? Does it just spread the damage over a period of time equally?
- Chirijiraden's comboing Potency is way to strong at 290, not even the DPS can reach that Potency, the only thing that can be higher is PLD's Spirits Within, when their HP is full and that has limited use because it's their Silence move. MRD only get's Storm's Eye at 50 and that's only 270 when comboed. And it also doubles their next counter's damage?!
- Hellish Slash is not very team-friendly. You're removing all you're team's DoTs, which I sure for a SMN, would be excruciating. Maybe if this class/job focused more on DoTs and this only effected DoTs placed by the user I could see some use but as it is, it lowers the whole teams DPS.
- Kiyomori is like a Foresight on steroids plus Parrying and increase to Counter Damage.
- Muramasa is extremely underwhelming compared to other skills.
- Free Lunch is a smidge too OP. Maybe if it just effected the user for an extended period versus a one use.
- A lot of your skills say that they decrease damage taken but no for how long.
- I would also recommend a skill that increases your odds of Criting. I'm sure you're probably thinking of adding PUG as a cross-class and getting Internal Release but I think Ronin or Samurai having their own to stack with it would be healthier especially considering you're main tanking tool comes from landing Crits.
- For utility purposes, I would have two separate skills for stun and silence.