Yea I want my Dark Knight again. Honestly i would prefer a whole new 2-handed sword class to be the base for Dark Knight.

Class: Soldier w/ 2-handed sword Job: Dark Knight -Melee DPS

However if it had to be from a current class I could see Dark Knight be a very interesting branch from GLD. It could even stay a tank and focus on more DPS to sustain hate and provide significant amounts of Lifesteal and enfeebling abilities. Drks always where awesome at pulling hate back in the day lol.