Your words don't match your proposed way of working. Emacs
maintainance quite often means bulk changes: new interfaces and
semantics are introduced, and things like the multitty changes and the
unicode changes necessitate global work (as do added bytecompiler
warnings). It is not feasible to do the update work only after
figuring out prospective maintainers for every file. The only hope to
get things like this done is to do the changes and let the maintainers
check for them. And merge time is certainly an important point of
time for checking it (though regularly checking for diffs in that area
is not amiss either for a maintainer actually interested in his code).
If your workflow does not permit fixes to be applied to Emacs CVS, the
only sane solution short of adjusting your workflow is to remove
org-mode from Emacs CVS. Only in that manner can it be assured that
bug fixes and interface changes and other things can actually persist.