It's easy to simply say "He's wrong". Can you show it? Can you provide the existing Illidan DH with enough design space to warrant development as a player class?
The answer is "None". You need to rebuild the class entirely from the ground up to give it that design space...and in that case, you don't have a DH. Blizzard could easily ignore that if it chose, but then we'd need to suppose it doesn't mind the various overlaps that woudl constrain the design of both it and other classes.