After sticking with the old web client for a long time for various reasons, I just recently switched to the new one, and this change in tab behavior is very annoying. I'm also kinda old-school and want to indent the first line of a paragraph when writing in my journal notes. Maybe I'll just switch to line breaks between paragraphs. I'm used to doing it virtually everywhere else (email, forums, etc), so it won't be that drastic of a shift, but effectively being forced into a behavior change by a design choice is still frustrating.
The UI must have changed since you wrote that, because the lower-right corner (in the new version) only has a control for switching back to the old version. Using the feedback form on the main site just leaves me with a message to post in here if I have feedback, so...here I am. 🤷♂️