Iron fists was lame anyhow IMO. The PT pyro is so insane. 3-4 shotting people vs a half assed melee spec that takes 3 times as long to kill things. Yeah u could take more hits, but who needs to worry about that when all your foes die before they become a threat anyhow??? Haha
The attitude in PVP is to deal the most damage as soon as possible. If you're a tank in PVP, you're at a distinct disadvantage because your shield will not work on force or tech attacks, working only on ranged an melee attacks. The tree is not viable for engaging players and provides no must-have tank abilities or possible game changers at the higher tiers - basically, you get the most out of it at the bottom tiers.
I'm more than disappointed in the disparity against defensive playing in PVP, considering they apparently nerfed some of the possible weapons for a tanking powertech. Once people realize you aren't pyro they'll either leave you alone because you're not a threat or string you up with stuns and CC like a pinata because it's funny like that, seeing as you have 1 stun-break ability with a 2 minute cooldown - gunslingers, sentinels and sages (along with ops and assassins...) have their way with you like all day.