The job actions trailer is just showing the new flashy things.
PLD got 3 new flashy spells. But I really doubt that it will add much to the job aside from looking even flashier.
So I don't see a reason for DRK to complain they did not get anything.

They obviously pick a job or two for a full rework in each expansion.
Dark Knight already got it in 5.0, so IMO it would have been surprising to see it completely reworked already.

I still believe that a lot can be done for the current DRK with simple cooldowns changes and the addition of some more oGCDs.
Delirium becoming a 60s recast is already a really good improvement IMO.