That's the past. Death Knights, as you know, start playing open world content at about level 60.
I don't play WOW, but is there an option for Death Knights to start at level 1? For example, a new player might wanna be a Death Knight, but may not want to skip all the early content.
No there is no option for a death knight to start at level 1. You cannot, however, be a death knight until you have leveled another character to at least 55.
So for a new player to create a Death Knight, he still has to go through 55 levels with another character, and therefore gets to see the old world content still.
No amount of careful planning will ever replace dumb luck.