I have conflicting feelings about this series.
The art is incredible and the characters are very expressive. The tone of the series is wonderfully fluffy and heartwarming but the writing itself feels like it lacks a focus, we go from set piece to set piece without a clear thread connecting them and our protagonists are awfully underdeveloped,
I severely disagree. All girls have a connection to each other in some way, and we get glimpses of each love's story. And each love gets a thorough and well-bred development. There is not one underdeveloped character in the entire bunch (unless you count the endpage characters?); the personality, habits, connections, feelings, and thoughts of every character are clearly outlined and given. And don't get me started on the relationships...I thought for sure that one of them was bound and doomed for mediocrity, but each one has its own flavor and sparkle, without any one being even remotely similar to the other.
Perhaps what is confusing you about the writing is how non-traditional (for Occidentals) it is? The writing splits into separate stories in the same world, focusing on different characters for every other arc while the collective whole is leading toward a final and clear end goal for the 'main' couple.
I don't particularly know what you were expecting out of this, I suppose. Because hands down this is one of the best series ongoing at the moment. And truth be told now that LOVE/DEATH wrapped up, I can count maybe 4 series that are arguably better (and not by much).