I propose that moderator flags which are declined should show up in the global inbox, as a way to more clearly and reliably educate the user on why their flags are declined, thus improving the quality of future flags.
This would not be displayed for helpful/disputed flags, as it would quickly become noise for active users.
While the recent warnings (Allow recovery from flag hellban) likely help, good users can also benefit from this feedback, even if they wouldn't ever reach the level of seeing the quality warnings.
From the linked Shog9 post:
For this to be effective, it must include feedback on how well you're flagging - closing that feedback loop should help our more prolific flaggers to become better at flagging
This feature aims to further improve that feedback, and shrink the feedback loop for everyone, not just the poor flaggers.