The PvP Shadow spec is completely off. I don't know who would use that build in PvP. First off, Veiled Shadow is almost mandatory. Shadowfiend is a DPS cooldown and gives well needed mana back. Fade is used quite often in PvP to kite melee.
SW:P is a small part of our damage in PvP and the two points for it is better put elsewhere, such as in Improved Mind Blast.
I would take full points in Harnessed Shadows because 3 Orb Mind Blast hurt.
Mental Agility<Improved Power Word: Shield. In arena you will find yourself shielding yourself quite often and even team mates.
You also need to glyph Dispersion and due to the state of rogues I would recommend glyphing Inner Fire. http://www.wowhead.com/talent#bfMoZZhrGdrkrkzro:smkVok