The difference is that the third game is perceived as a complete work of art; it's immediately obvious that the people who made it did so with love. It has a certain spirit. But the fifth game is purely about money.
Many people say that the Fifth Heroes is a commercial project, and that the creatures in it have been made more mainstream. Like, the developers lacked imagination. So what should we say about the first three parts of Heroes? There are no new ideas; only minor details have been added, or the scale of the game has been expanded (new races, etc.).
With that logic, you could say that there's nothing new, and that all TBS games are clones of KB:)
...The third game, in my opinion, is purely about money. The fourth game too. But the fifth game, to some extent, returns to the traditions of the second... the developers wouldn't have introduced so many minor details or thought through the world (note that in the fifth game, a complete and quite extensive world was created for ONE game; in the third game, the world was used for a whole bunch of games, including the Might and Magic RPG)...
