- What are the drawbacks of Heroes 3? (What didn't you like about it?)

better graphics (objectively)

Write "subjectively" too... I didn't like the graphics....

a much more interesting magic system;

of course, it's more interesting... in Chaos, there's the Haste spell, and in Nature, there's Speed, etc. definitely "much" more interesting... it's just a complete copy...

skill system;

and again, IMHO... yes, there's the possibility of mixing classes, but hero specializations have been removed, i.e., it's just a simple copy of the same thing again, and not individuality...
"Fork" is an obvious and unsuccessful plagiarism (subjectively)... lack of upgrades... reduction of monster options from one Castle, and considering the difficulty of building higher-level ones, you spend half the game running around with just three different units...

Comparing these games, in my opinion, is pointless... the 4th game isn't Heroes... it might be a good game in the end, after all the patches/add-ons, but it's a different game...