What would you like to change in Heroes of Might and Magic III?

This is roughly what you're talking about; they tried to implement it here:
http://heroeswt.net/download.php
This is a tournament version of Heroes. An attempt to make it not perfect, but at least balanced, so you can play with almost no rules (without having to memorize a long list of them). Whether it worked out is up to each individual. Some like it, some don't.

I understand everything correctly – it only works with the licensed version, right?
And how many people play with these rules? It would be nice to install such a mod to make life easier. Humans are creatures, and there's always a temptation to cause trouble or cheat. :D

Even if you set the difficulty to 1000%, a bot can't replace playing against a human.

I agree. This is about the fact that if there's no way to play against a human, then you should make the game as difficult as possible for yourself. In other words, embrace masochism. For example, try to get an achievement in the latest XCOM, where you have to complete the game on the highest difficulty level with a "terminator" mode. Something like that. :)