What would you change in Heroes of Might and Magic IV?

The connection between the first four words isn't entirely clear :D Please provide more details on how "mindless grinding" can be a result of leveling up. And how can it be "mindless" at the same time?

Without "mindless grinding," you won't be able to level up your hero, and even after leveling up, what will you do...? Send everyone to their doom, i.e., what Knight meant by "mindless grinding"! :D :D