A topic like "which level 3 unit is cooler"..:)
I voted for armor solely because of my love for taking the Dragon Utopia early, breaking through ГО and so on. However, there is a hero—Shakti his name—the only one capable of breaking a consulate's second-tier with a starting army, and if you add bless and some fire breath, even a third-tier—well, for him, offense is much more important than armor because the damage dealt by trolls is what matters, not the damage taken by them; the same can be said for Gosha and generally any variant with one pronounced superstack
Armor is incredibly useful in Dragon Utopias. Let me explain: in a utopia, the most important thing, strangely enough, is fire breath. Its task is ridiculously simple—to hold out for 1-3 rounds simply by skipping turns—with armor and without it are two different ways of taking it; what can be taken almost without losses with exp armor might turn into a complete waste without armor, and it's not even about the fire breather's hits but about the dragons' priorities—I've noticed that with armor they usually hit the fire breather, while without armor they may well strike the shock ducks/angels