Is there any reason not to move all my books out of author folders to sit in root?

[AudreyMedia]

I noticed the home screen UI has all the author folders, and then you click into them and then you see the books with covers. I would prefer a home screen with all book covers visible simultaneously. Alternatively is there any other way to do that

[Frenzie]

There are typically two reasons:

1. machine performance
2. human performance / enjoyment

Not necessarily in that order.

The device might start to display a folder noticeably slower after a certain point, let's say a few hundred files. And it's generally considered harder to navigate more than a few pages than it is to use a few (sub)folders.

But either way the same thing applies: you can try it, and if you like it there's no problem.

[AudreyMedia]

Are there any other options to change home screen UI?

[Frenzie]

See the top menu in the file browser for different start with options as well as adjusting how the covers are shown.

[AudreyMedia]

I'm thinking about this again, if I were to make themed folders and organize books with those rather than author folders, would that impact the metadata for author names or is this unrelated?

[jonnyl]

Originally Posted by AudreyMedia

I'm thinking about this again, if I were to make themed folders and organize books with those rather than author folders, would that impact the metadata for author names or is this unrelated?

That's unrelated. The book metadata don't get impacted when you move the files to different folders. (However, best move them in the KOReader file browser itself, rather than on your computer when connected, so the sidecar files containing the metadata are kept track of. Or make sure you move the folders along with the book files.)