Excellent review. My personal rating is higher, though I do agree the art isn't always spot on, it is 100% adorable. The story is one of the absolute best. This first volume, in particular, is really amazing in terms of it's writing. It is especially impressive when you consider that it was never actually a "real serial" in the magazine it originated in.
Part of the reason for the naming convention of the manga has to do with the fact that it was published in a magazine that was, in general, for one-shot manga, and not serials. When she continued making more stories about Kase and Yamada, Takashima-sensei kept the naming convention of having each chapter named as "Kase-san and something", leading to the general "Kase-san and..." reference to the series. But, at least at first, it was really a bunch of connected one-shots. Sure, the stories built upon each other and occurred in chronological order, but it wasn't quite the same as doing a weekly or monthly series, at least at the start.
By the end, I think it was more like a series. Especially since there were several multiple chapter arcs in later volumes.
As was mentioned by an earlier comment, the 2nd volume is already out, and is wonderful! I look forward to reading the entire series in print! Then I would love it if Seven Seas would pick up the sequel series, Yamada and Kase-san, which started publishing this spring in both Wings magazine and and the Flash Wings web magazine! (It picks up where the original left off...)