Though Japanese BLs (and J-Dramas in general) tend to be on the shorter end watch-time wise, this drama is a great example as to why that is. You don't need that much time or endless drama and build-up to tell a good story.
Kimi no Koto Dake Mite Itai managed to deliver something that felt real. It managed to deliver a story that you could easily see in your daily life, yet still keep your attention. It has lovable characters all around (especially the teacher's story), and delivers a sense of nostalgia and optimism that hits at all the right spots in the brain.
I fell in love. Every short japanese series is always a masterpiece. This one hits different. I don't know why this felt nostalgic to me although i never had a friend, crush or a lover. This is surely going in my top 5. I wish they would do another one together. I loved the summer theme. I loved the music. The cast was perfect. I really wish more series like this can be made. This is something i will remember forever. I know this may not be the cup of tea for all but for me its something that gave me happiness.
Give it a try. Unless you desire in-your-face romance, this drama should not disappoint.