What is your opinion about Heroes IV?

Well, there are games like Crusaders of Might & Magic or Legends of Might & Magic. So, this "sequel to the fourth game" could be named something in the spirit of "Generals of Might & Magic" (just an example). No one would make a 6th or 7th installment based on the concept of the 4th game, as even the developers acknowledged that it was not commercially successful, and many players simply found it to be a bad game.