I wish that the short story would have continued just a bit longer..

Yeah, like the girl falling in love with the boy... Negishi was not properly elaborated on, either. He's just the pianist that caught the girl's attention and etc.
It's also refreshing to see a pretty boy pianist with a shy and cute attitude. ( I always see pianists as classy and cool, though there are varieties; none are as refreshing to me as this.)
There really should have been more.