I think plogger was built with simplicity in mind, so that going one more level deeper adds one more click. Alternatively you can use other methods to make this "other level". What I have done is used tags to collectively create virtual albums that can go 1 more level deeper then perhaps a collection, or album. I am pretty sure that the developers are around, I just do not think they have much free time to advance the project. But really they gave us everything we need to make the application grow.
So heav3n, I doubt you will still be using plogger when and if another level comes out. You can certainly code it yourself or use an alternative means to getting to the same end point.