Why should you play a disc priest in PVP.

Yes, I'm not all that.

If you are a good gamer, you can play any class and be good at it. However, if you suck, then disc priest is for you . Why? Because, you can face-roll it easier than any other class, IMO.

Many classes and specs require you to face the target you are targeting. Most of the spells for disc priest do not require this. Thus, you need to just cast in any direction. Having to face the right direction just adds complexity to your class.

This can also benefit you when it comes to key-binding vs clicking. The feedback I've received from seasoned players is that a good key-binder will beat a clicker any day of the week. It has to do with the reaction time. Also, as a clicker, I notice times where I think I'm casting a spell only to find I'm not. I also have to divide my attention between what's going on and what I have available to click on. It's hard to hit a target who is running around you while you are searching for icons. Spell countering is hampered too. I will usually do a hybrid to where I'll key bind my 4 emergency spells around my direction keys.

Tangent: Priest were extremely OP back at levels 80 and 85. I used to be able to drag the whole horde army behind me while caring the flag in Warsong Gultch. When they stopped the ability to spam dispel on myself, it changed the level of OPness.

Then there comes to gearing your priest. If you can find a good person to play 2v2 with, you should be able to keep someone alive long enough for them to destroy a week 2v2 team. This is by far the fastest way to get conquest points for obtaining your better gear. You can easily step into YOLO RBGs with out much hassle. They don't expect much and quite often you actually end up on a good team that will carry you. Want to do better than 50% of the players in a RBG group? Pay attention and follow orders. Key point: I find a couple of mass dispels thrown on top of a major battle will usually turn the game in our direction. Many priest don't have a clue how game changing dispel is or won't Glyph into mass dispel. Nothing better than dissolving a pally bubble. So, get into some YOLOs, ask people to carry you in 2v2s in group finder, which they will, and you'll be geared in no time.

Ending thoughts:

Dispel, Dispel, Dispel
Bubble, Dispel, Heal,
Many Flash Heals are better than  one Greater Heal. IMO.
Research you class.
When everything seems on cool down, Nova.