Yes but untill fighters can TAKE tempest kensi woudl be a good thf or twf prc for them.
But, Desteria.. advancing two weapon or 2H fighting isn't the GOAL of this PrE. Like I said if thats what they really want they should create a PrE to do that.
I liek the idea of Dirfent prcs getitng the same style to the same place difrent ways IE a twf ranger takes tempest getts attack speed and thus deals more damage
A twf fighter takes Kensigets +damage/crit damage and thus deals more Hopefully similarly more damage, now you have 2 ways to get to the same end for teh same fightign style each are balaced each are difrent....
I'd rather they did PrCs instead of PrEs. PrE's always seemed like a half baked attempt to me.
For S&B you don;t look at damage and say they shoudl have the damage of THF or even get the same benifit from kensi lets be honest WHAT THF will take a prc that gives AC bonnus it woudl be totaly unballced becuase of the d20 a THF getting +10 AC would mean he gets hit lets be generus 5% less...
A S&B takes same PRC that +10 ac is goign to mean 50% less getitng hit it;s an absolute value BUT is it balanced no not really but does that matter NO why beacsue THF is not a defender style if a tHF wants to go defender they are already saying hey I'm not going to be good at this but i just want it anyway becasue it;s COOL.
Same thign for kensi S7B can takit sayign hey this isent as good for me but i just want it because it's cool.