Opting-out is provided in Special:Preferences#mw-prefsection-watchlist.
First off, now I can't even start a new talk page section without massive confusion!
Anyway. Where's the frequently asked question "HOW DO I MAKE IT STOP"
Even if the answer is only as below, you should include it. In fact, you should never have gone live without including it in the first place!
Q. How do I return to the old watchpage? A. You can't. We've decided what's best for you. Have a nice day.
When you had first access the watchlist, you had that pop-up offering you to opt-out. If not, I'm sorry about the inconvenience, but you may have a script or a gadget conflicting with that notice (and probably other stable tools).
In any case, there is an option in your preferences, Matěj gave you the link.
I went here immediately, since the optout popup is hidden behind the first.
In the future, please consider adding a "Get me outta here/Bring everything back as it was" button already to the first popup.
Btw, how do I get back to the regular talk pages? (Suspecting each wiki has its own setting; please add "luddite" option to globally make any and all new developments opt-in) CapnZapp (talk) 10:42, 17 July 2018 (UTC)
Have the opt-ing out button on the first pop-up is definitely a lesson learnt.
Concerning the talk pages, all talk pages are using Structured discussions on mediaiwiki.org. You can't opt them out. (And you don't need to sign anymore.)
The amount of white space is blinding. I realize this is not the place, but please tell the "structured" devs to add a "condense" option so less screen estate is wasted. Please don't "beginnerify" Wikipedia (or rather, do, but for new users)
Having to sign is obviously something I can live without, though.
Have a more dense version of structured discussions has already been asked. But for now the development is stalled.
Sorry that is unacceptable - I call that hit and run development. Revert back the introduction of new features if the programmers are unavailable right after release to polish their new stuff properly, that should lit a fire under their collective arses.
What the frak - if discussions are now linear only with no indentation levels, all hope is lost.
Please direct me to the proper feedback/discuss page of "structured" talk pages, so I can give my mind to those responsible: leaving development in this shape is unacceptable.
You can go to Help talk:Structured Discussions to share your feedback. On your way, I advise you to make a stop to the introduction page for Structured discussions, where you will learn more about indentations among other things.
"learn more about indentations" - why not simply say "indentation is not supported"? That page says "you don't need to indent anylonger" as if that's a good thing?! No wonder English Wikipedia rejected this mess. Luckily I'm not a frequent contributor to mediawiki, so I leave it to others to battle down this misguided and overwrought mess. The simple truth is that the Flow Project should have been shut down entirely; its team members dispersed over many other projects so their collective will is broken. It's not unheard of for smaller communities like this one to be usurped by a fanatical core of devs who ignore common sense arguments, and I will certainly not waste anymore effort here. For your sakes, I hope the flow programmers are ousted sooner than later. Signing off (because I want to), yours truly CapnZapp (talk) 09:44, 18 July 2018 (UTC)
And I hope the next time wiki isn't afflicted by hit and run programming. Implementing something and then immediately "stalling" development (without a clear opt-out path) is like a punch to the face, and deserves all the unpleasant feedback it can get. Have a nice day. CapnZapp (talk) 15:44, 4 December 2018 (UTC)
We still look for people who could help to announce new features and improvements.
