I would like to make a suggestion to display photo galleries without hierarchy, but with sections, more like a photo album.
Is it possible to add an alternative view to display the images of all folders and subfolders on one page, with optical dividers in between? The selected view (list, blocks, grid...) and sorting would apply within the blocks, but overall the order contents would be sorted in the same way as it is otherwise in the hierarchical arrangement on the left. At the beginning of each block, you could see the folder name that includes the images underneath.
A setting could limit the depth of subfolders to (i.e.) 5 levels (default). Folders below that would be shown as folders, which a click would open.
For example, you could scroll through an entire vacation trip grouped into folders by place or day or event (or whatever) without having to click through all folders. By cleverly creating the folders and subfolders, you could present this nicely.
What do you think?
Edit: Maybe the main area with the sections are moving up and down by anchor links, when the corresponsing folder is selected in the hierarchical view on the left side. And reverse, moving up and down the sections would highlight the current corresponding folder on the left side.
So it could be really just an additional "flat" view without affecting the whole usage.