In my opinion, I'm all for replacing the undead with dark knights!
I remember in Heroes of Might and Magic III they were my favorite... And here, I only had one chance to play as them. It's a pity...

And I don't really like the undead. Either I didn't appreciate them enough, or the units themselves are just... bland...
Their special ability is only good in the early stages, but when you encounter 10-15 dragons, they're done for.

I'm glad that the dragons look reasonably good next to other units like the ones from Heroes of Might and Magic VII. Before, they were weak, but now they're much stronger!
Maybe in the next game, they'll even surpass the black dragons... Just kidding!
A special mention to the skeleton archers (I don't think there's much point in continuing to talk about them)...