It hasn't been years but I wonder what Yuuji Kaku could have done with Ayashimon were he given the chance to tell that story in full. It had no time in Jump to lay the groundwork, but the Yakuza Yokai setting oozed style.

Ginka and Glüna was another series that was taken from us before its time. I think it suffered by being a little more cartoonish and straight edge in its storytelling in a time when Jump readers seem to be into more dramatic and edgy themes.