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But with two-sided bans, the number of options increases — the mentioned towns only need to be banned by one player, so pairs like red Dungeon vs blue Rampart or red Castle vs blue Swamp are possible.
With this ban system, the number of options is reduced to exactly two — red Tower vs blue Barb and Conflux vs Conflux. If the red or blue player attempts to deviate from this direction at any stage, they risk ending up in a losing situation. I will explain why.
First, each player must ban at least 5 towns from their opponent — Necropolis and 4 double-builds. This is unavoidable; if red does not want to get into trouble, he must start banning them — because blue has the last word, and he can use it to help red postpone a good brick build. I will demonstrate with the example of Necropolis — if red does not ban it from his opponent, blue will do so at the very end — and will play Necropolis against any other town, which for red is equivalent to defeat on this template — we have already established that. By the same logic, red cannot leave blue double-builds if he does not want to play against a double with a normal setup, which is also not healthy. Blue, of course, in response must act synchronously — he cannot leave such advantages in red's arsenal after being deprived of them himself, can he?
So, both players have already used 5 bans. Now, in turn, blue bans red's Dungeon and Castle — since he cannot leave these two strong towns to him — he loses the benefit of having the secondary skills of these factions, such as Angel upgrades and double-mana with Portal at the very least. And now red is forced to respond — removing Rampart and Swamp from his opponent, also two formidable towns.
And now each player has one Conflux left, as well as Tower for red and Barb for blue. And what will red ban in this situation? He can proceed in two ways — ban the opponent's Conflux for the reasons already mentioned above, and then it will be Tower vs Barb, or remove his own Tower, and then it will be Conflux vs Conflux. This is essentially the conclusion I reached after thinking it over. I could of course be mistaken, so if anyone sees an error in my reasoning — I will be happy to listen.