This discussion about Ghostwriter being a unique case because it stood out and was fairly popular in the west reminds me of another flop that was kinda a unique case imo, which is David-kun.
I think David-kun was also a fairly unique case in the sense that it gained a decent following in the west for a new comedy manga in Jump, but failed to gain readers in Japan. The people that read it also praised it very highly and I don't remember the series being criticized a lot by western readers. IMO it was generally a very well written comedy manga and is still to this day my favourite series that got cancelled.
Though I think the main reason it failed to gain popularity in Japan wasn't because it was badly written. It was mainly because it was full of western art and cultural references, that most Japanese readers probably never heard of. The only Japanese references it had, that I can think of, were references of other Jump manga. It even included western references that I had never even heard of before. So I can only imagine how hard it must've been to understand the references as the average Japanese reader who probably never heard of most of the references.
I think it had a lot of potential nonetheless because similar to Gintama, the mangaka created a universe where he could do whatever he wanted and get away with it. I also think if it included more references to Japanese culture, history and art, it could've gained some popularity in Japan. Though I might also be completely wrong with that assumption.
