I think Castle versus Necropolis... definitely Castle. It's a classic:
1) A Halberdier is stronger than a Skeleton Warrior.
2) An Archer is stronger than a Zombie, not only stronger, but also 100 times more useful.
3) A Royal Griffin, one-on-one, won't survive against a Wraith's regeneration, but in a group, it's naturally more useful.
4) Crusaders and Vampire Lords. Theoretically, the Vampire is stronger, and it has a second attack. I don't know, I really don't know.
5) No question here: Archliches beat Fanatics.
6) A Death Knight, most likely. Champions are weaker in almost every parameter; the advantage is only in the minimum damage.
7) An Archangel will easily win against a Ghost Dragon, even if it takes aging damage in return.
On the other hand, Necromancers have many kinds of cheesy tricks, like the King's Robe. There's the Skeleton Transformer, where peasants or Goblins can be upgraded to the "desired state." And then there's Necromancy as a skill. But everything is relative, as any turn can lead to either victory or defeat...