The best place to start is the shadow orb resource mechanic.
They just need to get rid of it. It's clunky and lame. It feels like ret pally did at the beginning of Cata, which sucked bad enough they fixed them but then gave us the broken prototype. No other class has to sacrifice 100k+ damage to use their only reliable source of crowd control, just sayin.
the lack of up front Dev Plague and a 3 sec 50% left over DoT was ideal for us. Now, it is just the same damage but over 6 seconds, which means no big hit up front (and yes seconds matter) and it is easier to dispell.
The DoT effect on DP is 6 seconds long now, restoring 6% of health per second with 3 orbs. The duration is exactly the same. I'm hoping it ticks initially and that counts so it will tick 7 times instead of 6. Except that would be a buff to our selfheals and GC wants us on our knees apparently.
Hmm interesting. Void Shift is VERY powerful, but it's no more than a Ret being able to HoP his caster partner. As much as I love VS on my Priest and hate it on my other toons, I think the problem is your off-healing which will be buffed in the 5.2 patch.
PoM, PW: Shield don't pop you out of SF which is great convenience if glyphed, but in 5.2 that will be even more powerful. I really think the Inner Fire change will be fine for PvP. I don't know if you were talking PvE or not, but if you have excessive utility, then your damage should be subject to that.
The way I've always thought of hybrid dps since I started playing in BC was that it should be slightly lower than pure dps classes as that's what they DO. As such, the utility of such hybrids should counter that slightly less/lower dps. I'm fine w/SPriests having utility as they should, but being as bursty as they are and having the damage they do I think is the issue.
So, as a hybrid, you should have the utility and not the damage. If you are complaining about the utility of Void Shift, or I should say accusing it as being the point of PvP concern, then I'd say you should play a pure dps class. Then you wouldn't have to worry about utility issues and just pew pew.
You can have one or the other: max dps or utility. As a hybrid you can't have both. Personally, hybrids should have utility and not max dmg. As a Warlock I have healing abilities but nothing close to Flash Heal that I can spam. Because of that option, no matter the mana cost, SPriest damage has to be put into check.
Some people will complain about that, but dude, you're a hybrid. You shouldn't do as much damage as someone who can't pillar hump to heal. Right?
Blizzard has long moved past the whole hybrid tax thing. It's no longer a consideration when balancing dps output. Shadow doesn't really have a lot of burst, I don't know what people are talking about. My DP hits for like 40k on a full resilience target and it takes FOREVER for me to use it, and then I have to decide "am I going to use DP in a vain attempt to kill that healer or PH to save my teammate from the warrior/dk/rogue/kitty that is eating his face." Mindspike hits for even less, Mind Blast hits for about the same as Mind Spike. So compare those spells to any mage nuke, chaos bolt, executes, what have you. Our DoTs are incredibly weak, probably the weakest out of the "dot" specs (SV hunter Serpent Sting deals more damage per tick than SW:P and VT put together and it's instant cast and spammable. Just an example, not saying SV is op). Mine tick for about 3.5k, or about 1% health of an "Okishbutnotreally" geared target, so basically nothing. You put dots up and pray to the wow gods that you will get MS/MB procs (which is indirectly being nerfed via glyph of mind spike).
Void Shift is really the only spell that really deserves to be looked at, and even then it's not that much worse than what other people can do on their long cooldowns and it's fairly easily negated if used unwisely. There are plenty of other classes that can offheal just as effectively as priests (outside of void shift) and have more cc and peels and burst. Shadow is only strong with a competent group of players that can support you and keep you alive long enough for you to do your thing. I don't see how that is OP.