Would you like to do it? I think all it would take is to move the code
there, set it in prog-mode (so that modes that derive from prog-mode get
to use this new code by default) and then make a few random tests in
various major modes (mostly those that don't themselves set
fill-paragraph-function).
BTW, could add a couple tests to test/automated, to try and make
sure your use-case is remembered?
Sure! Unless it's time-critical to get this done. My spare time
varies, but if I can do it in my own tempo, I can surely look into
it. :)
I've already spotted out js-mode as a candidate to make use of the new
code. It's currently borrowing comment filling code from cc-mode,
which results in bugs such as #19399.
-- Simen