LBE – minimal balance changes for Heroes V 3.1.

About 50 Elven blue units. A hundred Renegade Archers, but the ballista will manage to fire.

And how quickly can such a number be gathered? Clearly not, and the ballista will start to make a difference immediately (if it's lucky enough to eliminate machinery at the early levels), and as its HP increases, a hero with a well-developed ballista will be practically invincible in the early stages. For fast and medium-paced games, machines are quite balanced; for the late game, they are weak, and the only way to somehow improve the situation is to increase their effectiveness as the hero's level or the game time increases, as Durman suggested – I'm not sure, but it's probably impossible to implement.