DO you mean tactical mastery? If so it is very important and part of the build I linked.
And I have NEVER seen a build for an arena warrior over 1700 rating without deathwish and improved intercept. I ahve also never seen a build that had more then 35 points in arms. Improved mortal strike is a terrible talent.
i concur with meeks and if you are wondering you generally use DW as a preempt on fear IE zerker rage charge/intercept MS white hamstring zerker rage buff is almost up pop DW and continue attack sequence then as soon as zerker rage is back up pop it again
There is a reason why 3x/23/3 is a cookie cutter build :P Deathwish is pretty much necessary for fights with a warlock and impr. intercept coupled with the 4parts set bonus is almost godlike.
Talent Calculator - World of Warcraft
is what I spec for PVP. cheaper executes are nice and I value impr harmstring more than blood frenzy (especially for my 2:2 where my mate plays a priest who needs any breathing space he can get for burns, heals and more).