Shined up real nice.
Redirects the new post page to the classic post page
You may also like Popup Blocker Script.
WordPress.com has removed the preference to edit posts using the classic interface. This user script forces a redirect to the classic interface when the new edit interface is visited.
If you don't already have one, install a browser extension that allows you to run user scripts. Then, visit the URL below:
Also on Greasy Fork.
If you don't like this script or can't use it for any reason, there are other workarounds available.