Support for the sorting and filtering of photos that are in deep structure libraries (aka multiple levels of folders where the Plex "section" is at the top level). This only seems to currently be possible at the "root" level, but if each "album" us stored in it's own sub-folder, you lose the ability to sort or filter once you navigate down into the album.
are you saying structures like
my photo / 2015 / 06 / 01
like that?
Yes, like when you have a Section named "Holiday Photos" and which contains a single directory in the file system that contains sub folders for each year (e.g. 2015, 2014, etc). You can navigate into each folder with no problem in the current product, however the filtering/sorting is only available at the "Section" level and not once you are within each sub folder.