I agree with Petya's opinion.
This raises the question of bonuses from stables, watering holes, and artifacts. In my opinion, only artifacts should be taken into account. If we leave the bonuses from watering holes and stables, everything will remain the same, i.e., players will send their hero to the stables/watering hole, dismiss them, and in this way try to find their hero with 2k movement points if they need it. Of course, this is more expensive, but there are many cases where 2k movement heroes are necessary.
Regarding stables specifically, this has nothing to do with the 2k hero bug, and secondly, it is one of the main features of the castle, for which (among other things) bidding takes place. I believe that removing such a feature as the special hero buyout in the castle, obtaining +400 mana there, then dismissing this hero and "digging" him up in another city is wrong. It's simply a weakening of the castle and a impoverishment of the gameplay.