Usually, I would argue that stories of this type be sent back to the drawing board (literally!). There are lots of "eh" manga volumes out there filled with "eh" stories that give the reader little more than an idea: oh, here's a rogue with a heart of gold.
True, there are plenty of "eh" volume-length narratives out there too. The difference: it is much easier to convey something (anything) with a longer piece than with a shorter one. This is why writing a strong five-paragraph essay is harder than a whatever 15-page paper. A short essay has to convey its point clearly, succinctly, and concisely. A 15-page paper can ramble away with the surety that some worthwhile nugget is buried somewhere inside.
A good short story can't ramble--all the parts have to work seamlessly together. Likewise, a good manga short story comes down to a seamless interaction between text and imagery. A good manga short story with no arc, only a premise, relies almost entirely on its art.
To be continued . . .