I really don't like the new designer, so I routinely switch back to the classic designer. However, when I do so, there's a problem with all my workflows which involve 'send email (V4)'. The body of the email is stuck in html code view, and I can't toggle out of it. If I flip to the new designer I can toggle between html and regular view.
So Microsoft is forcing me to work with the new designer, when I don't want to. (I'm finding it buggy - strange things keep happening to the dynamic fields I'm using in my emails and flows that have been running successfully for months are suddenly failing).