That’s really annoying indeed. Should we start to doc on docs-dev?
By the way, I second partially @blackwarthog on this comment:
Maybe layers themselves should load/save/serialize/deserialize their nodes. Not a single function.
This would ease to deal the different versions of a layer and compatibility.
As you are way more used to Synfig code, could you please explain me what libraries and their issues you talk about?
I do agree Synfig must ‘be stabilized’. But some stuff was very outdated and pretty poorly usable for current days.
I’d vote for writing automatic (unit) tests to improve code and search’n squash bugs whether hidden or not. Actually, I proposed that here in forum. But I couldn’t make almost anything related, because there were (is?) many unused stuff in ETL headers and in Synfig core library, for example. And lots and lots of things on them I don’t understand. So, I would barely know how to test them 
Nevertheless, I’d be glad to help on this: writing tests, documenting synfig classes in code, restore doxygen doc generation, … But, as I said, I couldn’t go alone as I don’t know the code as you guys know.