Sorry but I strongly disagree, all other DK is there still hope or a way to win.
There you have Raxxar sitting at 6 doing WAY better than all other DK only valeera is on the same level but lucky she is balanced with the cost.
Rexxar-> ??? Gain tempo a lot of time with the AoE, refill your hand slowly with MUCH stronger minions to the point it's not possible to come back again unless OTK, why not just remove the discover BS and make it totally random that would be so MUCH more balanced.
Guldan -> save AoE, only the hero power is scary.
Jaina -> Play the fatigue game with a proper deck.
Uther -> useless without OTK.
Anduin -> fuck your own board, still need cards in hand for okay predictable effect.
Rest is kinda a joke and doesn't win on their own.
That's total bs.
Depends on matchup heavily. Rexxar is great against slow decks without win condition like Odd Warrior. Many matchups he is useless in because he is too slow. Against tempo or combo decks you don't want to even draw Rexxar because it's a dead card in your hand.
Have been playing hunter for a long time and I can tell you many times Rexxar doesn't do anything. There are specific matchups where he is totally OP (slow control decks) but tempo/combo completely crushes you if you try to play slow game and drop Rexxar and then start building zombeasts, you will be dead before you can even create and play any useful zombeast.
Guldan is much stronger which you can see in wild format where power level is higher.