Sure, it was a blast burning across the map with Imrik and his 19 dragon doomstack - An outrageously unbalanced game, LOL, that really just has a passing novelty value.

Still, Imrik's dragon taming side-quests are great, so nobody wants the lose those.

I think a good compromise might be some algorithm for escalating in-fighting between jealous dragons each battle.

• With just two dragons, and the chance infighting is low (5 or 10% chance per battle)
  
• With each additional dragon add another 5% of aggro, until a 19 dragon strong army is pretty much doomed to implode. Ha ha.
  
• Of course, if you've got casters with the right spells, and/or commanders with very high battle authority you might still hold together a pretty large army of squabbling reptiles.