Inexplicably wondrous and enchantingly beautiful.
If you've ever seen an episode of Mushishi, you probably have felt some of what this manga will make you feel.
If you've ever read Omoide Emanon, you probably have felt some of what this manga will make you feel.
I can fathom no way to improve it, other than that I want to feel more of what this series made me feel.
A perfect series can end one of two ways. It can end with all ends tied and all arcs closed, or it can leave you with a longing to erase your memory of the series so that you can read it for the first time again. This is the latter, and by God... what I would give.
Read it. it will improve you.