You're right! I just fired it up and was able to install Advanced REST Client (the only thing I regularly use Chromium for) without logging in.
When I first installed it - less than a year ago - that wasn't possible.
That's a step in the right direction, but you're still only allowed to install extensions from the Google-owned Chrome Web Store.
Have you tried Vivaldi?
It's supposed to be from the original team of Opera.
Also based on Chromium, but at least not a clone of Chrome.
I tried it. The UI is HTML5 based and good by the way. But it's closed source. With so many shit hitting the fan these days, I don't want to invest my time in closed products if there are alternatives.
i still use the last presto version for reading big chunks of text
The presto version has a great downloader and rss reader that I still use.