|mediawiki/extensions/VisualEditor : master||SaveDialog: Hide options bar when empty|
I don' think this is for showing "progress" but rather for "warning" the user when they are about to run out of space, as we aren't encouraging very long edit summaries.
I think T194458 was correct in not showing any indicator until you get to the final 100 characters. Getting to 400 characters in an edit summary is very rare (probably <1%) so making counter part of the normal workflow would just add confusion.
In #2 it is not technically feasible to wrap text around the counter, so it would either reduce the width or the height of the area available to type.