I don’t know your areas of interests, but for fun here are some matches to each criteria item:
レンタルおにいちゃん is a nice, short series (four volumes), with no anime adaptation.
I just finished アオハライド. The anime covers maybe about half of it, and seemed to conclude. It seems there was an OVA that leads into the latter half of the series, but I don’t know if there was ever any plan to add more reasons.
ふらいんぐうぃっち is another that did get a one-season anime adaptation, although the manga has continued quite a bit since.
Although I’ve only read it in English, Nisekoi had a decent first season anime adaptation. The second season, on the other hand, rushed the story, and ultimately was a disaster in my opinion. (If I remember right, they resolved a whole plot point by adding some brief text at the end of an episode basically saying “and then this happened”.) The remainder of the series was never animated.
I know you weren’t specifically looking for exact matches to those individual criteria, but those series immediately came to mind for me =D
(Also, all of them have had book clubs here on the forums except for Nisekoi.)
It’s pretty common, and for a variety of reasons. I imagine it’s mostly stylistic, based on the author’s feel for what’s right for the character.
