I have been using some post notices lately, especially with new users that are not aware of some standards like writing a longer answer with some explanation rather than a single line.
A user has helped me letting me know that some of these users did improve their answers, so that I could remove the notice.
I'd like this to happen automatically. I mean, the system could warn me when there is a change in order to make things happen faster. This way, I could remove the post notice as soon as it's possible without manually checking all of the answers that I added the notice to. Of course, even if the system tells me it's back to a good quality standard, I'd still check the answer. I just think that it would come in handy to have a virtual help.
I'm not sure how we could do this, but a way could be to use the answer score? Since a low answer score triggers an automatic flag for low-quality content, why not use the same thing for this feature? If the score rises, the system would send me a notification saying that the answer has been improved since the post notice. I don't know if there would be a better way to do this, the developers will know better than me on this.