if you have to buff old classic end game items like anathema (and even thunderfury) maaaybe your power budget is out of control 
You made a choice for damage or defensive every time you activated dispersion.
No they are upset that in the 2 globals it took them to kill you you could apply 2 dots that might kill them 20 seconds later if they had no stamina and did literally nothing to try and help themselves.
thats dishonest.
those 2 dots (that could crit if you had despair slotted) were enough to outright kill quite a few classes and if not, get them in the range of dying instantly to shadow word death.
being able to dot at max range and delay till they get to you and hit you 1 or 2 times then disperse for 6 seconds was at least 12 full seconds of no ability to counter play other than the few classes who could dispel it (pally and you guessed it. priest.)
this is coming from someone who plays a shadow priest in raids now and pvps a bit too.
problem really being is they cant seem to get the middle ground in alot of the pvp balancing so its either on or off.
you can still have some success in pvp on a priest but its alot more situational than it was.
6 sec penance is wildly strong. Whats wrong with that?
Actually this is a good point, they should do the same for hunter bow too instead of just handouts from new raid. The quest line items like that should last atleast until AQ. It would also give people a reason to keep raiding MC.
How about atleast giving benediction HOLY spell damage.
Equipping Anathema allows shadowpriests to use their most iconic ability: dispersion
There, fixed.
There were absolutely a few situations where dispersion could turn the tide and get you a kill you would not have gotten but so what? That happens every 5 minutes for every paladin playing SoD.
They could have made adjustments to dispersion either in CD or duration but gimping Spriests in order to use it is terrible implementation especially now that instant burst damage is ridiculously high.
Be honest, when was the last time you fought a Spriest who ran dispersion? Why do you think that is?
because damage is king in ranged battles and they moved the rune .
its no wonder nobody is running it .