So, while I know Jatmin likely can't do the proper rendering as it depends on if Yuoki has the original resources/assets still outside of completely remaking the graphics, would a temp fix to use the various directions as a fake up/down angle work?
I'm not sure how exactly it would look, but it would at least make it look a bit better if what I'm thinking can work out. Pretty much having the up/down use the diagonal directions as needed, though I don't know if the North/South will be able to benefit from it as well. I know the east/west can at least, until either the source assets are shared or graphics are remade.
/Edit
Just noticed I placed this in one of the addon mods, I'll post it in the main one too. Can respond to either.