As a complete amateur I'd love a chess engine that can point out my mistakes, explain its own moves, and suggest better moves, in human terms. Like, this move would pin the white bishop. I don't know if this would be AI based or simply a search-based engine that scores in abstracted ways such as giving points for tactics like pins and forks, controlling the center, protecting the king, etc. (Typical chess search just scores based on piece and position and looks ahead farther than a human brain can handle.)