Guide on adding a new model, animation, and creature to HoMMV

@footman, sharing knowledge with fellow members of the Heroes community is a significant gesture; don't be stingy and do it, but do it when you can and want to. Years, even decades, may pass, and people passionate about Heroes will remember you! I am confident that with its current achievements, Heroes 5 has every chance of remaining as enduring as the legendary Heroes 3!

But now, what are the chances? I may have a negative attitude towards Heroes 3 (I'm a fan of Heroes 4, but I respect Heroes 3 for its AI), but it has virtually no chances. If you compare Heroes 3 and Heroes 5, it's simply a clone of Heroes 3, but in 3D, and not the most successful one in terms of all parameters:
1) Let's start with the AI, which is relevant today. What prevented the developers from simply taking the AI from Heroes 3 and not reinventing the wheel in the next four installments (this applies not only to Heroes 5).
2) I won't compare the graphics of Heroes 3 and Heroes 5; I'll just say that there were games with better graphics than Heroes 5 even before it was released, and without all sorts of unjustified bugs and functions that don't work together or don't work at all.
3) Gameplay and balance: here, things are the most normal. Necromancers dominate everywhere and always in the late game (almost). All that's missing is an artifact to raise liches for 0.1 units of energy.
4) Modding: this is the most interesting part, specifically the fact that it is very limited by the ingenious decisions of the developers in the style of "we are the developers, so only we can do this." Listing everything that cannot be done because of them or can only be done with workarounds (hex editors and scripts) would take too long.
In my opinion, Heroes 3 is still popular because its source code is available online, but as for the code of Heroes 5, everything is clear to everyone.