What is your opinion about Heroes IV?

You missed a lot more bugs, the caravan feature that ruined the game, the daily growth, the inconsistency with the series (killing off some races or mixing them up), and the dumb magic system where one clearly dominated the others...

As I already said, you're used to the third Heroes game and its gameplay. The fourth one is like a revolution. Some people liked it, others didn't. It all depends on which part of the Heroes series you started playing. Accordingly, you get used to the gameplay and its nuances. That's why other parts seem "strange."