Heroes 4 is a strategy game, not an RPG. Just run around with your hero and kill everyone.

The characteristics of "RPG" and "strategy" are definitely not mutually exclusive in meaning, as they describe different aspects of the game. In general, Heroes borrows a lot from D&D, as mentioned above, and therefore RPG elements must be present. It's just that there are more of them in the fourth installment than in other parts.

Personally, I've played all versions of Heroes.

I believe you.

And believe me, I can appreciate each part for what it is.

"I don't believe you" (quote). And I wrote why earlier. Moreover, I'll add that if you're really expressing your opinion about the gameplay of the fourth installment, and not just engaging in a pointless provocation, then playing against Shnurov will be useless for you; you won't even understand how you'll lose.

To Shnurov

This is primarily CragHack, which was in the TOP-3 (or even TOP-1) in at least all versions of Heroes except for the fifth.

Could you provide some historical background: is CragHack an official map or an online map? Because if it's an online map, then the TOP-1 in the third installment was supposedly Antal, and then the Baevs, and there's no multiplayer in the first installment at all.
But if it's an offline map (online isn't my thing), I'd like to know more. For example, I'd like to read some walkthroughs (if they exist), try to repeat the results, and even better, play against him in several tournaments, if he's still active. Because the results of the "ancient fathers," at least the local Russian ones, don't seem too impressive when checked now – they're good, but not more. I'd like to find an exception and see for myself. If not in the fourth installment, then at least in the one where he's still strong.