Social poll.

1) To allow a replayable quick battle to work unilaterally, while the hero doesn't spend mana! And let the neutrals cast spells.

Tell me specifically how this option is better than this:
When attacking, a window appears to choose between quick battle or manual battle, and when choosing manual battle, pressing [Q] results in an instant battle completion without the hero spending mana?

Want to take a Hive with a Hydra? - Sure, choose quick battle when attacking.
Want to quickly deal with weak neutrals without spending mana? - Choose manual battle and press Q.
Want to win a difficult battle without losses? - Choose manual battle and don't press Q.

And I'll answer myself what the fundamentally different thing about a replayable quick battle is:
Compared to the option I proposed, it allows you to assess the enemy's strength less responsibly, accurately, and attentively, and to assess whether you can defeat the enemy with a quick battle without losses. And in case of an assessment error, it gives you a chance to correct it.
So, you attack some weaklings and think: "Oh, I can get away with a quick battle here."
But then, bam - and an Angel takes down your hero. And in one case, you can correct the situation, and in the other, you don't have that opportunity.
The replayability of the quick battle gives you more confidence when attacking a weak army with the intention of defeating it with a quick battle, because if something goes wrong, you can correct the situation.
Replayability gives you, in certain cases, a way to peek at the exact number of creatures and choose:
if there are a minimum number of them in the group, a quick battle is sufficient.
if there are a maximum number, fight manually.
Without this possibility, you either fight manually to be sure of the result and spend more time, or you save time by taking a risk: you might not lose the battle, but the cumulative losses from such battles can decide the outcome.

Therefore, one-sided replayability is a cheat!