The thing that sets this series apart from other romance series is that it's not really about the romance. It's about the characters. (I'm joking, but not really)
From the start, Tasuku seems like he's pursuing a doomed romance. Because of this, the author's able to explore Tasuku's crush in greater depth, and in turn explore that part in any adolescent's life when you start to become fully conscious of the world around you. Tasuku's crush on Shia comes about because for the first time in his life he's realized this older girl who he's known all his life and has barely spared a thought for is a living breathing person with an inner world separate from what his lifelong impressions of her have been. And as Tasuku struggles to understand this inner world, he and Shia both deal with their own personal shortcomings, maturing into adulthood in their own ways.
This is a story where it's perfectly understandable if Tasuku's romance realistically fails, because the way his crush serves as a vehicle for his and Shia's character developments is perfectly satisfying on its own.
Though, the author does such a good job of developing Tasuku's maturity that it would have felt unrealistic if Shia didn't return his feelings, because good god does he become an encompassing part of Shia's life. By the end of this story Tasuku's more mature than most MLs in college age romance comics!
It's understandable that some people would want more out of a story like this (more timeskip content, more fluff, just more in general) but I think it's perfectly fine in its short format and does everything it sets out to do without branching off into the unimportant stuff that turns a lot of SoL romances into total drags. It's a focused work, with no distracting side romances and filler arcs. That said, the supporting cast in this is hilarious. This author knows exactly how to populate a cast with quirky characters that never waste an appearance, and I particularly liked seeing Tasuku's brother and sister and their goofy family dynamic. If there's anything I wanted more of, it's them!