Just today I tried to add an image to a post. Classic Editor allowed me to publish a resized image within the post. Gutenberg does not offer this. I ended up having to re-edit the image off-line and then re-upload it.
Also just the task of adding tags has become troublesome. Typing tag names in the field leaves me hanging for ages while WP tries to find an existing tag (which I know are there) and half the time can’t even find an existing tag. Then if/when it does appear I select it and then it disappears completely. Why is this extremely simple function suddenly so difficult.
I am not considered an expert in HTML but have enough experience to make simple modifications or fixes as needed, so I would have almost welcomed a plug in like Gutenberg but it is such a step backwards and not at all simplified the process. Send me back to Classic Editor!