Nice! I also wonder if a simple preview before post won't force people to read it and fix it.
Discussion
This might help solve the issue but it also adds a layer of friction to using the app. Given that the instances where users need to edit are minority we would be adding friction to the entire posting process to solve a minority posting issue, which doesn't make sense.
I actually think people are pretty bad at it. Our follows are good writers. Followers not so much.