I have a few suggestions for a few stuff and would really love to see it added since me and my friends play this game alot.
1. Wario and waluji and princess peach. ( wario and waluji would be silly and I think the princess peach could have a float ability like yoshi but a liitle different. )
2. world 8 bowsers castle map would be cool and a rainbow road map if you can
3. enemy power up. it can summon a goomba or a koopa with its ability.
4. new races. i really lke them and race with my friends so i would like to see more.
5. invisible mushroom. so like metal and door it wears off but makes you invisible
6. music changer. when you press esc you can change the music when in-game. ( maybe just for host or for everyone )
7. admin. instead of giving people host you give them admin and they can do everything you can do except change the server size or make it private and ban/kick you.
8. cars game mode. everyone is in a car.
9. Bowser map. in the map it has Bowser n it and the only way to win is to kill him and get the star.
10. and the last one is custom color. basically how it works is you put in a texture id and its printed onto the character. ( maybe a selection of textures in the colors and then it has a brick texture and mushroom texture and stuff like that t would be awesome! )
if any of these can be added in the game i would be very happy :)