Quite often am clicking through long lists of MP3 files or similar, to search for some certain song, where i do not remember its exact name, or abbreviation (in my old vinyl collection), so that i could simply use F3 to search the contents. When i reach the end of the list, i can either push the down arrow, which isn't the best way to progress, or the PgDn key.
My suggestion is, if i'm on the last or second last item in the list, that PgDn in Opus would not retain the cursors position in the next page, leaving a "hole", but would set the cursor in a "seamless" way, having the item selected on top of the list, that was the next one to the selected file in the previous page. I don't know, if this makes sense for other users, but i think it would be a smart solution. Maybe it would also be possible the other way around, when using PgUp.
Edit: an alternative would be, that pushing the down arrow on the last item of a page would act as a PgDn, with said properties.