Bad pvp design is, when you as DK needs to press 5/6 buttons to pull your big bursty cooldown buttons while some other classes (like DH) only need to press 1 or 2 big cooldown button to burst. (and even full heal you will doing it) so its an offensive and defensive in one button.
As unholy DK you have to combine these cooldowns to deal even close to the same amount of damage a DH for example does with one button.
There is a reason why some classes are played more then others in PvP because they simpy require a lot less effort do the same thing or even better.
This is insanely bad pvp design and I really struggle hard to understand Blizzard, a big company, doesn’t understand this when it comes to balancing. Because this is just one of many examples.
Simple solution is to just combine some of these big bursty buttons. It would not only balance but also make the gameplay feel a lot more enjoyable.
Wake up Blizzard.