I'd say that story quality among original VN's(mostly Japanese) is indeed quite usual thing. Tho among all types of vn's existing such level of quality is very rare, - especially among "nswf"-oriented.
If got motivated enough about story you can check vndb.org for top of best VN's released in any format and any language. Many of them Japanese/psp only, but there are a lot at least English/PC localized.