I buy Japanese light novels so Im used to it, but I dont think it would do well in the west.
The two examples you posted are really not high quality stuff, made for book cover.
To work in a global market anime style needs to be toned down. For example my favorite japanese light novels published by Tokypop. Look at these covers and you will see the difference
That kind of thing. I think Tokyopop had pretty nice covers.
The examples of art you posted are just not suited for something like book cover.
I live in Japan and even 300円 light novels have better fitted stuff.
Sorry if I sound harsh, its just my observation.