In 2.3 people had so many more marks than honor. Honor was possibly the worst its ever been and it was an age that tried to adjust the decent honor gains via Honorable kills system that they had.
So honorable kills were changed to no longer take the player’s rank into consideration in 2.3 and with diminishing returns it basically made it feel like honor didn’t exist anymore.
The marks and lack of honor was so bad that in season 4 they removed the diminishing return cap (but the HK honor was still pretty low) and they also added the Concerted Efforts NPC back to the game with a new quest that gave you 314 honor repeatedly when you brought one of each mark to him.