Dwarf vs. Wingayel (Lands of Outcasts)

Against the Armageddon tactic:
As I understand it, everything is calculated based on the fact that the damage from Armageddon is not dealt to dragons, Titans, and Priests.

Well, this is a common situation, but 15% from luck and 15% from defense also reduce the damage (probability of the spell taking effect + if the hero moves later than the bears, pikemen, and berserkers in the first round, you can try to target fire immunity with a rune; if necessary, this can be done in subsequent rounds).
By the way, I didn't claim that Armageddon is a universal tactic; it's just one of the real options against a cheaty Wingael. In other cases, it's preferable to have a more developed hero and more units than Wingael.