Bay of Destiny

Three cities don't justify themselves because Knights become overpowered.

Not at all because of that; if there were Mages instead of humans, it still wouldn't justify having three cities and wouldn't change the strategic aspect. The main problem is that maps with a large number of cities are usually very dynamic, and this map cannot be described as such.

The Ring of Speed should be removed completely.

There's no extreme imbalance in this artifact, but I would completely remove the Sandro's Cloak from the game. Dark magic is already overpowered, and this just adds to it... In general, in terms of balance, I think it would be more logical to prohibit building an artifact shop in all cities.

Two dwellings are enough; more are not needed. With huge armies, some skills become irrelevant.

That's nonsense. The concept of "knowing how to play Heroes" includes knowing how to properly develop a hero depending on the type of map. Some skills are beneficial on small maps, others on large maps, and so on. If that weren't the case, the same universal hero development option would always win, and then the question would arise: "Why are other skills even needed if this universal option is the best?" Let's just remove half of the skill wheel... Adding dwellings is perfectly acceptable, and they won't create any imbalance with the Knights if you're so afraid of them (and if you reduce the number of gold mines and remove the Capitol, even more so). I think it's okay to leave one Mentor in each capital; having them on every corner is also unnecessary. I would even suggest removing all Mentors and placing one under guard in neutral territories; this would immediately increase its strategic value