The synopsis from IMDb says the film is about 'a group of Yokohama teens look to save their school's clubhouse from the wrecking ball in preparations for the 1964 Tokyo Olympics'. Looking at the trailer, it certainly looks pretty (as you would expect of a Studio Ghibli film) and the song is beautiful. I think it will be the story and the way it is told that will determine how good the film is.
KOKURIKO-ZAKA KARA will be released in Japan on July 16th.