The 5 on Maiev made me think it was a 1-5 scale. Doesn't make it nearly as bad now but i think a majority of the DH cards are 3 or above.
I gave very few 4s overall, but I gave five DH cards a 4. So, you can tell that I agree that DH got a ton of strong cards.
Ultimately, you can only play 30 cards in your deck. The ones I gave 3s got a 3 because I imagine they will see play across multiple archetypes of DH.
The ones that got 2s got a 2 because I think they will be restricted to probably just 1 type of DH deck. (Command the Illidari, Chaos Nova, etc.)
I hope that clears things up.