What is your opinion about Heroes IV?

Luck should double the damage, and morale should grant an extra turn. It's all very simple.

To whom should it apply? The main problem with all such debates is the stereotypical views they generate, 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 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 for 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 that his protectors survive. And then, if he survives, he will cope with the problem. That's why parties consist of several heroes, like a joint raid. And Luck is considered to be when a hero was supposed to die but survived. So, in this matter, the developers did a GREAT job; they adhered to the logic very strictly.