Level 7 is weak; it can't be compared to Archangels, who can resurrect and fly very fast (seemingly faster than anyone else).
You are mistaken. Archangels are not the fastest; they are slower than Phoenixes.
Living cavalry is almost as good as undead cavalry, and it can be upgraded for free in the stable on the map, and its damage is increased at range.
Champions have always been inferior to Black Knights, and increased damage per cell doesn't help them. :)
Monks are not inferior in strength to Liches; they hit with a cloud, but what's the point? I never place my units nearby. And monks also have no meal penalty.
Monks are also weaker than Liches, and by a lot.
The only thing that people can't definitively counter is skeletons. But you need to know how to gather them, and skeletons are very slow, and you can slow them down until "better times."
However, the first level of humans is the second strongest, second only to Centaurs :), plus skeletons in quantity, but this should be compared not with the first level, but with all of them – quantity can decide the outcome of the battle ;)
And also, in the Castle, there is the hero Adela, with innate diplomacy.
And for the undead, there is Isra, for example!