Personally speaking I'm biased towards 14/0/47 being a dedicated raider. However if you're dead set on keeping your all shadow build to help yourself in PvP then as suggested above you should drop improved fade and get full misery. Given that its a passive effect and applies to all magic damage done by the raid its quite possibly one of the best debuffs in the game and you'd be mad to not take it. This of course assumes you want to raid that is.
You see, I'm not entirely sure what that build is intending to accomplish. you've taken 5/5 in both tier 1 shadow talents which is odd in that a raid build would arguably only take one of those in order to progress down the tree, wheras a pvp build would only take blackout and ignore spirit tap.
If you were aiming for a shadow pvp build I'd probably say something like this would be more appropriate. It takes out the points in the shadow tree that are not useful for pvp and places them in the disc tree.
http://www.worldofwarcraft.com/info/classes/priest/talents.html?5002320120020000000000000000000000000000000050232410241100251551 If you were aiming for something more raid oriented I would have said this (usual variations aside), it eliminates the pvp talents for a build emphasising long term damage and efficiency:
http://www.worldofwarcraft.com/info/classes/priest/talents.html?5002120130000000000000000000000000000000000053250210240123051551 And if you were after a more mixed shadow build, something like this could be good:
http://www.worldofwarcraft.com/info/classes/priest/talents.html?5002120030000000000000000000000000000000000053252210241103051551 Either way, a lot of this is already in Khalane's excellent shadow priest guide which you can find within the first few pages of the priest forums.