Is this your first expansion?
Devs typically don’t make too many tuning adjustments until mythic raids are released. They’re currently analyzing data and preparing the raids for RWF.
They also look for higher mmr arena data to determine what pvp adjustments need to be made.
The casual bg crowd that whines about getting one shot because the opponent popped four burst cooldowns while they panicked and did nothing don’t have the skills and experience to properly determine what adjustments need to be made. There’s also potentially a large gear disparity.
Spriest has powerful burst, sure. Powerful burst is great. It accelerates games and forces opponents to make quick decisions. It also means if you don’t execute during a win condition, your opponent can come back and win during theirs.
Spriest has never been sold as an easy to play spec. It is easily one of the most difficult to play solely because of all the utility it can provide.