If you're looking for some challenge, one good feature missing to me is being able to directly copy-paste code from the code view so i don't need to save the current view to a file and then open it in my editor (just like you mentioned in your post 
)
As for the rest, i think philmoz's finsig as of today is just enough for generating stubs, etc.
I've though about doing a version 2 where you get real edit functions (including C&P) and maybe two windows to allow you to do a CHDK sensitive diff function between two C files. That way only line of code that will actually compile to assembler are compared - whitespace, comments and format changes are all ignored. The diff function in Notepad++ is quite good but still tedious for comparing things like boot.c files.
At that point, I'd probably delete all the functionality that compares stubs files, replacing it with a more generic "find code that looks like this" function that works with the two windows mentioned above.
Oh, and with the different addresses for ROMs and now some of the code being copied to RAM on startup, I probably need to remove some of the current built-in memory range checking.
Things to think about ...
