It won't happen, so it won't. I forgot, he's smart :). And you can defeat the AI even without any tricks.
And the gates, which you suggested using to block passages, I saw a STUPID AI, an Oblivion, approach, and I don't remember if it was with its left or right hand, but it destroyed the gates in one move :). Just stupid, instead of dancing around the gates for 3 turns, asking for permission, it just took them down in a second. :)

Well, an Oblivion is an Oblivion :) I'm not suggesting using gates to defend against flyers :))))))))
Although you can, if you summon them right next to your archers.



Added 5 minutes later

But at the start, this ability is almost useless. Only blocking with gates and removing retaliation.

Well, in the 5th game, this was the main tactic for Inferno. Don't you think so? In the 6th game, the situation is even better, as they gave low-level archers.

By the way, necromancy also depends on the initial size of the army (the percentages are almost the same as for the gates), and at the beginning, it's almost useless as well.

And also, I really like the unique building-teleport. It's a great thing in a strategic sense. Although it's not overpowered, of course. And the worm is very interesting, does it really not attack its own units?