FDK is basically the melee fire mage, which doesn’t feel good, which is the reason why fire mage is getting heavily reworked.
I mostly play PvP on my DK so the pain is even worst but I can feel the trouble my spec has in PvE as well. It is a lot of work and effort to provide the same (if not less) results than most other classes.
I have some suggestions for PvP talents that are completely undertuned like Shroud of Winter, which could basically be the remorseless winter Bolvar used against Sylvanas, for example making our RW give us a lot of avoidance rogue style or immune to ranged spells. Frost definitely lacks defensive options. The D&D pvp talent anti-heal is also a joke. 1k per tick, yes.
We need attention, definitely.
Suffer well brothers and sisters.