Who should it benefit? The main problem with all such debates is the stereotypical views they evoke, caused by the fact that people often consider the first thing they liked to be the optimal one. How many people do you know who started playing all parts of Heroes at roughly the same time and, ideally, immediately played against other players and in tournaments, because playing only against the AI significantly slows down and even distorts perception? I only know one...
Let's return to the question of Luck bonuses. In all parts except the fourth, the hero is a commander. For him, the main goal is to achieve the objective – to kill the enemy and capture something. Therefore, it is logical that luck is about killing more monsters than expected. In the fourth part, the hero is a kind of warrior or mage who has taken creatures to help him, which essentially protect him. For him, it is logical to consider the primary task to be SURVIVAL, i.e., to ensure that he himself takes less damage and the protection survives. And then he will live, he will cope with the problem. Therefore, parties with several heroes go together, like a joint raid. And luck is considered to be when he was supposed to die, but survived. So, in this matter, the developers are doing a GREAT job; they adhered to the logic very strictly.
Heroes 4 is a strategy game, not an RPG where you run around as one character and kill everyone. I agree that the hero should be the main one, i.e., without a hero, the army is nothing (well, almost). I personally have played all versions of Heroes and believe me, I can appreciate each part on its merits. Luck in the 4th game is simply inconvenient, it's kind of strange; in what other games (I'm not talking about Heroes right now) is there luck of this type? It's just hard to get used to it. As for the developers, I'll say this: where is 3DO now? It doesn't exist anymore; you can thank Heroes 4 for that. Although the developers themselves are to blame; they got into debt and hoped for luck:D