About the promotion rule, I'm not that sure that you are correct, waiting 1 turn to get a rook is a big deal, what can the oposite bishop do in 1 turn to turn the tables. A rook can win you the game. Also now you have to pay 1 turn from rook to queen but I don't think this will come into play unless very weird situations like many pawns vs minor piece and the rest of pieces the same, although the rest of the pieces will be used to capture/block pawns!
About the promotion rule, I'm not that sure that you are correct, waiting 1 turn to get a rook is a big deal, what can the oposite bishop do in 1 turn to turn the tables. A rook can win you the game. Also now you have to pay 1 turn from rook to queen but I don't think this will come into play unless very weird situations like many pawns vs minor piece and the rest of pieces the same, although the rest of the pieces will be used to capture/block pawns!