A touchscreen mode would be nice for people that have tablets running windows and have no keyboards.
Maybe a pause button could be added to the corner of the screen so you wouldn't have to wait for the song to finish or fail to go back to the main menu.
and for the other modes, there can be touch controls.
For Taiko mode, there can be a touchscreen drum like the T-aiko app on iOS & Android
For Catch the beat, there can be a touchscreen joystick to control the character.
Maybe a pause button could be added to the corner of the screen so you wouldn't have to wait for the song to finish or fail to go back to the main menu.
and for the other modes, there can be touch controls.
For Taiko mode, there can be a touchscreen drum like the T-aiko app on iOS & Android
For Catch the beat, there can be a touchscreen joystick to control the character.