your questions regarding the game rules (improving the interpretation).

Trading is a good alternative to sacrificing, but is the community ready to accept it? There's a category of players who will say, "I don't want this castle, and I definitely won't give up that one."

So, it's not surprising. Heroes is a form of entertainment; people play to relax, have fun, and there are many players who simply don't like playing with many castles. For example, I wouldn't be happy if I got something like Inferno or Tower; why would I want to pay 500 for regeneration? It's no secret that often various useless things appear. Considering that, having to give something extra in a trade isn't a great idea.