I think it will always be necessary to use an external program to
download photos. Geeqie simply provides you with the ability to call
other programs via plugins.
I use the command line interface to gphoto2.
I have an icon on the toolbar to point to a plugin .desktop file
The desktop file calls a shell script
The shell script calls gphoto2
To use gphoto2 with your method of storing files, it would be necessary
for the shell script to:
Call gphoto2 with the option --list to get the list of files to download
Use the option --show-info to get the date of each file, and then create
the necessary folder
Use the option --get-file to copy the file to the destination folder
If you want a something easily integrated into Geeqie, unless a
ready-made solution already exists somewhere on the interweb
unfortunately I think it will be necessary for you to do a bit of
scripting to get the result you want.