The most challenging maps for you.

I think if they remake Heroes 3, the most successful approach would be to keep the same gameplay style, the same factions, the same turn order, and the same balance. They could add 1-2 new factions.
Improve the graphics and make the AI smarter. Also, make the AI very strong in battles, up to the level of a strong chess player, depending on the difficulty. Then the game would be priceless.

And so that ordinary, newly-minted players would perish at the hands of this AI on the first level, thus cutting off the replenishment of the ranks of Heroes players!
P.S. Don't touch Heroes!!! In my opinion, everything is fine, and making the AI smarter is already absurd - firstly, where have you seen skilled bots? Secondly, who would need such bots that crush everyone... the game in online mode would completely lose its meaning, even if it's without AI, people will just dominate the neutral creatures...