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.
