Hello! I was the said user on the steam forums that used this strategy.
I just registered because I wanted to say that I didn't realize that I was using a "cheese" strategy or playing the game incorrectly. I was just trying to figure out the best way to play on hard. I actually did the opposite first, where I tried to create no mythologicals and just spam as many Greek units as fast as I could (with 2 barracks and a siege workshop), but the bandits beat me up easily.
Anyway, I think its hard for us gamers to know how the game is intended to be played. I agree fully that if this strategy wasn't intended, then it should be fixed as soon as possible. I think its important to keep in mind that the fixes could probably be pretty confusing to people who don't religiously read the patch notes. Like the "Mythologicals can't attack keeps" change for example. If I didn't read that change, I would be confused as heck as to why my Minotaurs weren't able to beat up keeps, and I'd probably assume the game was bugged.
If Mythologicals aren't intended to be used this way, then maybe it would be a good idea to do something like each mytho you make causes the next one to cost even more? Then it would be easy to use in emergencies, but you couldn't just keep spamming them like I did.
Anyway, I'm glad some interesting discussion came of this, and hope you guys figure out a good solution.
Edit: Also, although a lot of people probably like the custom game options you've got going, it might be a nice idea to create some predefined scenarios. That way I would have known I'm not supposed to play the same faction against each other.