Yes, that way the balance will be much better. Although dragons as seven-level creatures were quite well-balanced. It's not even worth mentioning that bosses in the army (it says there that they can still be recruited) will create a monstrous imbalance.
In my opinion, everything is done quite logically. A dragon should be a truly powerful creature, and now, in order to defeat even one, you will have to make a lot of effort and suffer significant losses.
Bow down and hear our cry,
Our earthly rulers falter,
Our people drift and die,
The walls of gold entomb us,
The swords of scorn divide,
Take not thy thunder from us,
Take away our pride.
G.K. Chesterton: English Hymnal