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

By the way, here's a question. The situation was this: I got a Conflux Castle. My opponent got a Fortress. He had a Serpent Nest guarded by 50-99 Storm Elementals. His army consisted of 9 Wyverns and 10 Lizards. I don't understand how he broke through...
My Nest was guarded by 50-99 Air Elementals, and I couldn't break through with 8 Mind Elementals. I guess I'm just a complete noob.

Are people really not playing at 200% anymore? :( Because it's actually interesting.

M-200 players definitely exist. However, in tournaments, they play with a patch that gives 2500 gold and 5 ore at the start, and also removes obelisks and external markets to avoid starting imbalances. So, it's more like 190%. And in the season, you can freely agree to play without the patch. Especially since not everyone has it.
Regarding the Storm Elementals, there's nothing surprising about it; read the Phizmig.
Firstly, Mind Elementals deal half (50%) damage to any Elementals (also Undead and everything immune to Mind magic).
Secondly, Storm Elementals (unlike Air Elementals) are ranged attackers, meaning their direct damage is 50% of their ranged damage. That is, in melee, Storm Elementals hit 2 times weaker than Air Elementals.
So, in a pair of Mind Elemental and Air Elemental, the Mind Elemental loses half of its damage.
And in a pair of Wyvern and Storm Elemental, the Storm Elemental loses half of its damage. By launching the first attack on 10 Lizards, that's why they were taken into battle.
Plus, there was likely a Beastmaster with experience-based defense and a defense stat of more than 5 for the swamp. Possibly, he was skillfully using healing or a tent.
For the Flax, it would be good to use Lightning or Chain Lightning, as they deal 200% damage to Air Elementals, especially since there are plenty of good mages. Comrade Luna and Comrade Inteus have Fire from the start, so it's quite possible to get an experience-based curse, which turns the damage (2-8) into damage (strictly 1). That is, Air Elementals deal almost no damage.
And counterattack on Mind Elementals is also a well-known tactic; they don't have an upgrade anyway.
Mass Slow is weaker in this situation, but it's also possible; Grindan or Labeta can easily use it from the first level.