The current design for beatmapsets with only one beatmap is this:

This is different from what stable does where it only uses one panel:

perhaps the design could be adjusted to be similar to stable:

I'm not sure if this is going to happen or not, but it sure as hell isn't going to look like that.
What about just displaying the version of the beatmap and its star rating?

I'm considering modifying the artist text to display the mapper just like it does in stable. So in the picture above, it would say IAHN // Monstrata. This makes it so that the redesign does not omit any information.
Update: I think a dot looks better than two forward slashes to separate the song artist and mapper.

Longer diff names would push star ratings further to the right thus giving visual inconsistency. (Not a designer, just my 2垄)
Moving this out of milestone. It's clear we do not have the bandwidth to implement this just yet.
Is there a design for this? I'm looking to rework how the carousel draws its panels so a design would be nice to have.
We haven't finalised the UX or design for this just yet. Needs further discussion, so stick with what we have for now.
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I'm not sure if this is going to happen or not, but it sure as hell isn't going to look like that.