comment upload rewrites entire comment form to set #default_value from #value breaking other modules

In comment_upload.module around line 124 I run into the following code comment:

// Rape the comment form.
// Comment_form was not build to rebuild a form and fetch values from $form_state.
// To preserve changes made by the user, we build the part of the form we just received,
// mapping $_POST values to #default_values.
// Because rebuild is TRUE, $_POST has been validated. Nevertheless this is insane.

(emphasis added)

This has been in the comment_upload module code for ages. I hope you all agree this should be fixed. The culprit actually is the comment_upload_value_to_default() function. This recursively rewrites every #default_value in the form array to #value. (wait... WHAT?)
Rather than rewriting the entire comment form I'd prefer to create a solution whereby only the file upload itself is handled.

this is evil:

foreach (element_children($build_form) as $key) {
  if (isset($form[$key]) && isset($build_form[$key]['#value'])) {
    $form[$key]['#default_value'] = $build_form[$key]['#value'];
  }
}

I was up all night trying to figure out how to debug a date field in the comment form (via time_tracker). So when I figured out the above in comment_upload which was causing problems, I thought it best to report this instead of trying to build a workaround in time_tracker.