Especially since that plot doesn't really sound like a novel. It's something more suited to a picture book or a short comic/animation. "Leave them wanting more," applies a lot more to those formats. There's way less content so it's way easier to go overboard and add too much.I agree with the Chief Editor tho, agreed of her idea to NOT continue the book. Of course, there are books that require an explicit ending; however, there are also others that are more effective without. Perhaps subject to interpretation, or that the answer was very clear but only hidden. If I was Chief Editor-san, I would held my ground to discontinue it.
Anyways, that aside, the story seemed promising and the art is really good!