General questions and discussions.

Yes, I am one of the developers.

Well, in any case, I'm still willing to wait a year, but no longer; after that, I'll simply get tired of it.

This isn't the first time I've seen statements along these lines, and they surprise me somewhat.
The current version is complete and playable. If Heroes and HotA interest you — play it. If you're getting bored — take breaks or quit. Of course, a new version can spark interest, but Heroes is not the kind of game that should rely solely on constant updates and people's craving for novelty.

It's clear that many want updates to be released more often. But at the moment, they are no longer critically necessary; it's mostly additional content and further improvement of the game. And they don't appear quickly or on a schedule.
Therefore, I see no reason for anyone to force themselves to wait for a new version. Nor do I see any point in highlighting the fact that someone has grown tired of waiting.
There are exceptions, for example, when people quite rightly express outrage that certain unpleasant bugs still haven't been fixed. But at the moment, these are isolated cases.

Will there be an introduction of neutrals, like fangarms and satyrs?

As already announced, a leprechaun will be added. Other new neutrals may also appear in the future.