Dear Linas,
What about compiling .luc files for otf font cache and load it instead of .lua ones? Or maybe use .luc for all of the lua files, like PYTHON does with .pyc files? The idea was written here: http://tug.org/pipermail/luatex/2013-March/004101.html
This is already the case with luaotfload v2, and will of course still be the case with v3.
In the future would be good that font cache files could be loaded using kpsea library.
Good idea. I don't really have time to test carrefully right now, but I think it's already the case if you pass the good arguments to kpse*.
Thank you, -- Elie
