Since Arms now gets its own Enrage there isn't much for an Arms warrior in the Fury tree for PvP other than Cruelty and Piercing Howl.
From the Prot tree an Arms Warrior gets:
TM: Great for stance dancing, spell reflects, etc..
Last Stand: Extra health on demand.
Imp. Revenge: If your getting focused it should let you stun one of the attackers, thus reducing your incoming damage.
Improved Disarm: This is the main reason for going this deep into prot. 10% extra damage on target on demand, twice every min (assuming Disarm and Shield Break are on different CDs) is great. Sunder up a healing shammy/pally, then Shield Break them and your looking at a very large chunk of extra damage taken.
http://talent.mmo-champion.com/?warr...00000000000000