ASW – Alternative hero leveling.

In all other cases, does it make sense to create city classes?

If the mod is only standalone, then there is no point in having hero classes.
All cities will have classes, because this will increase the unpredictability of the opponent, diversify calculated risk, and the gameplay.

Added 5 minutes later

And if, in addition, a typical hero + an atypical city appears, for which only 1-2 heroes are suitable (or 10-20%), which are difficult to find in the tavern, then it's not ideal.

Refresh the page, because your message changes many times after mine.
Random city class? Who said it will appear automatically? Yes, it's easier to implement that way, but even so, you can find another hero for the city in the tavern.