feh, gqview, xv, pornview... All of them are image viewers (and sometimes a little more than viewers, or a little more than images). All of them belongs to media-gfx category. Even aview, which is an aalib (ASCII Art Library) based image viewer, also belongs to media-gfx. But xnview belongs to x11-misc. It should be at media-gfx category too.
It will stay in x11-misc for now.
Would you mind to explain the reason of why this won't be fixed (for now)? And if it will be fixed later, why not mark it as LATER?