I agree with you that it would be more interesting with these game modes, but I do believe their future absence was meaningful. In a competitive game, it can be quite annoying to lose on an opportunity for coins just because of another player messing up or just being bad. However, it can also be fun and interesting to carry a team where the others are of varying skill levels. It really is double-edged. As for single player mini games, they were replaced with item mini games, which I believe are a good replacement; they are short and concise, unlike some of the single player ones from MP1. Although fun for the player, it can make other players lose interest.