First half of your sentence: we actually discussed this in editorial/marketing awhile ago, but in traditional publishing, thematic anthologies don’t sell well, so we’re being a bit conservative at the moment.
Second half of your sentence: exactly! Shorts are great to fill in gaps, and they also add extra surprises to an issue, so that’s our main purpose for them now. Some will probably also be pilots for bigger series.
I loved Maiden and the Fish, too. <3 We're slowly building up a backlog of shorts, which is also the reason submissions opened up for them specifically in December.