What they did to gedit is really a disaster. One day I needed to launch some simple GTK+ app to check something I changed in configuration, so just typed "gedit" into console, saw a window and thought that client side decorations has broke. It took me a while to notice that what I saw was actually intended. UX of this app is now awful, and it's a massive downgrade, as it used to be just fine.
Why is it a downgrade? That it changed doesn't make it a downgrade by itself. You can still do the same things that you could before. Just because the menu bar and the tool bar isn't there anymore doesn't mean that the features are gone, they are still there and you may have to do some relearning. You learn a tool once, and use it many times. It's of course unfortunate that the old design wasn't perfect; maybe the new one isn't either, but the idea is that in the long run it will be and at some point you just have to change what is there even though what you had technically wasn't broken.