They've been A/B testing it for weeks.

Huh, not seeing that yet. But did see that huge catalog image at the bottom that did away even with the ctrl+end way to get to news, which now vanished again.
From g2222's screenshots, definitely wasted space with that top wishlisted thing. But if those two lists mean that they finally made some use of the space currently wasted with "featured", at least that'd be an improvement, though those lists should also be more compact, definitely.

Does GOG still offer an RSS feed for the news?

Yes: https://www.gog.com/en/frontpage/rss

Nice! Thank you.
How sad that RSS and Atom feeds are falling out of fashion.

This seems to be a change: when viewing your library and clicking on a game, it now displays the info immediately instead of sitting there and thinking about it for several seconds. Also, I find that screenshots load faster.

Yes. A change made by jpolgesek about three weeks ago. Reported here:
https://www.gog.com/forum/general/gogrepopy_python_script_for_regularly_backing_up_your_purchased_gog_collection_for_full_offline_e/post3849

Oh nice. It sure makes checking updates a lot better.

You can now manage Galaxy cloud saves through the web browser:
https://www.gog.com/account/cloud-saves/page/1
Important: the following alert appears on that page:

Would be nice for there to also be a way locate that url without a direct link and also two extra buttons/toggles on that web page, one to disable automatic syncing and another for wiping all saves from the cloud without affecting the local saves.

There is also this new support page: https://support.gog.com/hc/en-us/articles/18730340487709-Review-your-Cloud-Saves-to-avoid-loss-of-files?product=gog

Any one else got that stonking big search bar at the top of the main page? Seems a good idea but it's way too large as it is.

Indeed. It is good that it's visible instead of needing to look for the magnifying glass icon and click it, but:
1. It's too large
2. Once you click it, everything vanishes off the page.
3. If you type in it, you get a list of matches that takes up all the screen just to display name and price of a few titles, while the old search bar just overlays the matches over a small part of the screen and also lists year, dev/pub and OS and allows wishlisting with a click, while the new doesn't.

Yes, it seems a bit of a WIP and definitely not as good as the original search bar. Let's hope it's reworked soon to bring back the previous functionality - plus at the same time they make the thing a whole lot smaller too!