Posts from RTF is a global modification that replaces all towns in the game.

Here's a question that arises: shouldn't we make the Cabiri 4x4 units and revert the Earth elementals back to 1x1?
I think it's a bit silly, because even in Heroes 7, it's stated that Cabiri are lesser fire spirits.

A 4x4 cell first-level creature is unlikely, but you can adapt it to a larger size for other units, or extract 4x4 earth elementals from the Polish mod.

WizardNecromancer started creating elementals from the 6th game.

there are other units as well, but if we add them to the Fortress, it might be better to replace the gnoll mages as well, for example, with some other units instead of medusas or green cows.

Cool snakes. But I'm quite happy with the current roster, and losing the interesting feature of having no flying units would be a shame.

It's also not good to have absolutely no flying units – how do you take a city? You immediately want to go through the machines and teleport – I think you need at least one flying unit.

What's the point of sending a single flying unit behind the walls? To be slaughtered? + Shamans have the "earthquake" spell.

...I am quite happy with the current roster, and losing the flying units would also eliminate an interesting feature.

we have a flying unit at level six (by the way, the new version will feature models from the Polish mod)

So, is it there or not? :D - You've confused me.

Coatls and Dragon Riders

This is already a matter of combat tactics, and everyone has their own – a complete absence of flying units will create problems, including during battles in arenas without fortifications, obstacles, etc. Earthquake only partially solves the problem. Of course, it's your decision, but balance is a fragile thing; in my opinion, it would be desirable for each city to have at least one flying unit and one ranged attacker.