Promotion shouldn't be compared to castling/en-passant here. A game without castling or en passant would be similar enough in spirit that we could call it a "c

Promotion shouldn't be compared to castling/en-passant here. A game without castling or en passant would be similar enough in spirit that we could call it a "chess variant". Removing promotion, on the other hand, would result in a wildly different game. I actually suspect it'd be impossible to win against any non-beginners, making it more similar to tic-tac-toe than to chess.