A lot of what you want in your list will be possible with the new templating system that we are implementing, but that still has some bugs in it.
I'll answer your questions in your post below.
This is an *ideal* list, based on what the store owner has seen. I can imagine similar functionality implemented in a slightly different way. Bottom line, the thinking is to minimize clicks until a user wants to see more detail.
As I said, most of it will be possible with the new templating system, but you'll need to code it. As you are a webdesigner (I assume you are), this should not matter.
There will be a gallery that contains only sub-galleries -- so I would prefer to not display "No images in gallery" for that high-level gallery. Can I turn that off?
Easiest would be to replace the language definition in the language file, so just replace the text with nothing (search in english.php when your sites language is english, for the text and delete it).
Is there a way to not display image counts? For example, I have a gallery with 4 sub-galleries. The gallery has "22 images" below its name, and the sub-galleries have [14], etc., next to their names. I'd rather skip the counts completely.
use .rsg2-galleryList-totalImages{display:none;} for the images count
And can a thumbnail open a page with more than one image? For example, now a thumbnail opens an identical image in a larger size. Imagine the thumbnail is a show. Can the detail page have 3 images of that show -front, side, top, for example?
No, not at the moment, and probably not with the templating system, you would have to hack the code