Yeah there’s no real room to buff Blood or Frost, and not that much to buff Unholy. I think they’ve pushed those cards about as hard as they can without breaking rules about stats and such.
Generally looking through the list I think there’s room to buff: Saurfang, Graveyard Shift, Anti-Magic Shell… maybe change up the corpse requirements on some of the other unholy cards, but I don’t see much room to buff much else without breaking it. Which… they might do that, sometimes they like to do that.