NHF – new heroes for Heroes V 3.1.

Then ban the horseshoe and the lion's crown altogether, especially when they're used together!

You're comparing apples and oranges: artifacts and specializations. Artifacts should have a significant impact, while specializations should only provide a small bonus, on par with a simple perk (just one!). At least, that's how it works with many other heroes. Take the specializations, for example: by level 18, they give +9/+9 to the stats of the hero's preferred unit, which is about a 35% increase in damage and survivability for that unit. Just one unit! But here, the luck specialization gives a +30% damage bonus, which is equivalent to the entire army.

And in reality, it will be less than 30%. The fear factor, the risk factor, and the counterattack factor will all reduce this number.

The element of surprise works against both sides. So, reducing the impact of luck because of this is just another myth. Statistics of results, at least, do not confirm this.

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K'suda will be 10 times stronger than Nibros. And yet, no one seems to care about her....

You're comparing kilograms and meters, global strategic and local tactical specializations (combat). We're only talking about tactical specializations here, so compare it with the tactical specializations of other heroes. As for how things stand with some K'suda, I don't know, I haven't seen it.