hi
Can you please say something positive ?

I think I see what you mean. I've finish a site made in Drupal for a book distributor (no shop). But with feed importer, and all the extras fields and mappings, it's quite easy to import the products, But , there's always that problem, specialty in Portuguese, where there is a lot of accents. So the author "João" is different from "Joao", or "joao" or " joao" (a empty space).
Something for Genres or Publishers.

I don't know how the core of csv imports works, but I guess, if no ID or matching string is found, new ones are created.
If one imports 100 books, and has to rectify 20, it's always easier (not to mentioned competitive ) .
Or simply restore a backup, and redo to match the corresponding author, genres, etc ,names and upload again.

But yeah, this is probably very complex for my knowledge, but looking at EP, it looks "simple". But I guess I'm wrong.

Best regards