I am really big on mitigation and I think that is one of the biggest aspects that is needed in PvP right?
The defensive stats (defense, shield, absorption) are all not that good in PVP at the moment. This is because defense and shield (and therefor absorption) only work against melee and ranged attacks, not force and tech (and a lot of the attacks which players use are force or tech).
This is also why a lot of PVP tanks basically use DPS gear with a shield off hand (shield instead of focus because using a shield does raise your defenses quite a bit, and some of your talents are completely wasted if you don't use a shield).
The idea here is that while going full tank will indeed make you take less damage and have a bigger HP pool, in many cases you'll be be more effective in your role if you can instead more effectively help peel enemies by doing more damage.
Looking quickly at your spec, in my opinion I would at least recommend putting a full 3 points into aim, and focusing more on utility (speed boost after Jet Charge, lower CD on Grapple).