Balance in Heroes 5.

They won't give you Armageddon, but they will give you Phoenix; the probability is much higher than with Armageddon. Anti-magic won't help, and neither will archers. There's nothing that can help against Phoenix. If they don't give me Phoenix, I'll create a Shield for the Gargoyles and attack enemies with Shock or weaker spells if Shock and Armageddon aren't available. Regarding your first idea with archers, it's not viable. Do you think I'll put Gargoyles in one stack? I'll divide them into seven stacks, and while you're trying to kill them, you'll be gone. :)

Well, you got Phoenix. :) Do you really think it will defeat my troops before I defeat yours? Or am I supposed to, like a newbie, immediately attack it with all my forces? :) It's a summoned creature, and as soon as the main army dies, it will disappear on its own. :) And don't tell me that's unlikely. :)
Regarding the Shield... interesting. :) Will you also divide the Gargoyles into 7 stacks with it? And then cast it on each stack? :) In any case, it only absorbs 50% of the damage. And how will you attack me with weaker spells if I have Anti-Magic? If there's no Anti-Magic, I still have Unique units, and the ability to resist spells, so your spells will hit with a 50% chance. Or maybe I'll get 5th level Resurrection in my guild. :) You kill the archers, and I resurrect them (while other units calmly destroy the Gargoyles). Or, let's say, those same 7 stacks of Gargoyles, and I have them as Cursed Ones and the ability "Arrow Shower." The hero will attack all 7 stacks in one turn. How many turns will your units last if my units are also attacking them? :) We also have a hero named Wingael, who gives a bonus to initiative at the start, 2% per level. A few times, use the tactic "Hit and run to the city," and that's it. :) No more Gargoyles. Just take archers and druids in his army, divide them into 7 stacks, and attack. Before your hero goes, all my archers will attack. After that, I simply buy my way out, and the hero with his unit ends up in the city, where he can be recruited again. Considering that the archer unit isn't very large on the 3rd week, and I'll definitely build a Capitol, I'll have enough money for this. :) Of course, there are also "War Chains," but you still have to find them. :)

There are many options. You just need to know how to play your race. :)
And one more question for you, how many games have you played on the "Heroes of Might and Magic" series? Or have you only tried fighting with friends? Or have you only fought against the computer? No offense. Just answer honestly.