In reply to Andy M..

The pinned bar is a positive side effect of what we were really setting out to do, which was to eliminate the issue of scrolling an editor within a larger window that also scrolled. It was never an ideal experience. Being able to manually set the editor height was a symptom of a problem.

We've been using this form of resizing for a few weeks now and you very quickly get used to how it works. Try going back — you'd wonder why WordPress ever worked that way to begin with. As someone else with OCD who lost their treasured resize handle, I feel your pain, but only so much.

On occasion, people will want to shorten the height of the editor. But because it now simply grows and shrinks with the content, it's a much nicer experience overall and you don't actually lose anything by not being able to control it.