The latest expansion pack has been released. Now, certain things are clear.

...”Pop culture pandering” is the loss of one's own style and the desire to please everyone...

I'd like to point out that when "Heroes 2-3" were popular, not everyone had the opportunity to play them; only those who had their own PCs at the time. The computer industry is developing at a tremendous pace; compare the graphics of Heroes 3 and 4, and the difference will be minimal, but Heroes 5 is a leap forward! Moreover, most players began their acquaintance with the series with Heroes 5, because nowadays, only those who don't need a PC don't have one. I myself tried Heroes 3 after playing Heroes 5, and it didn't impress me; it's old and visually boring. Heroes 5, despite all its flaws and "holes" (and the more complex the game, the more holes there are), is much more interesting. The computer industry still has a long way to go to become more perfect. ;) But the results are visible year after year, which is a good thing...
As for the similarity of creatures, there is a certain mythology, even encyclopedias of mythical creatures, in which they look a certain way, and they should look that way in games, regardless of the publisher, perhaps with some minor stylistic differences!