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So, let's paint a picture: it's the 2nd month of the game. You're sitting in your castle on your piece of land, a demon is freely roaming the map, attacking neutrals, capturing mines, and collecting artifacts, and by the end of the first month, it reaches level 17-20.
What do we have? The Necromancer is lagging behind in development by 4-5 levels, has almost no artifacts, and also lacks resources. You want to upgrade some unit, but there's not enough money left to buy an army. Conclusion: there's no decent army. You can't win with just vampires; if the Princes don't blind the enemy during an attack, they'll get completely crushed. You'll have about 15-17 Liches, enough for two squads. A ballista will destroy half of the first squad with its first volley. There's a 60% chance that you won't have a Plague Cloud on the first turn because Imps almost always move before the hero. If things go well, you'll have Cave Goblins in your army, and if they reach the Skeletons or Zombies, the result will be disastrous. If the hero is Marbas, the demon won't even care about your Plague Cloud. A Tent of First Aid also removes the Plague Cloud, unfortunately.
The Dark Elf's mana problem is easily solved: build a Mage Guild and use the Magic Attraction skill, and if the hero is Ianna, they already have it from the start. And, of course, hit-and-run tactics are always an option. The Hunters go invisible for 3 turns, and the Sorcerer throws Fireballs for 3 turns without being punished. Then, they safely retreat if things get dangerous. There is, of course, a risk of getting hit with Shackles, but without risk and a bit of luck, you can't succeed in Heroes.
I wasn't talking about the ballista; I was talking about Wingard's troops. He's the most famous fast attacker in Heroes.
But I think the opposite is true: in the late game, you need much less control over your troops than in the early stages; there, it doesn't matter if you lose a dozen soldiers or three dozen. But in the beginning, every soldier counts, and I don't like those who intentionally prolong the game. This is usually done by beginners because they need to "settle in, gather a huge army, and then dominate everything." Later, they realize that speed is often very important.
Added after 12 minutes
And according to your logic, any player playing Dark Elves is weak because they rush. But maybe they rush not because they're weak, but because they understand that Dark Elves usually lose spectacularly in epic battles, especially against Necromancers? Your logic on this is questionable, very questionable.