We changed the default mouse click behaviour to double-click for KF6.
For me this was surprising, so I would like to raise a few questions here that might as well be answered with: "sure, we are", and I just did not see it because I am a bit out of touch with KDE development news (and modern ways of communication in general). Personal and biased opinion follows. But here are the questions first:

Are we handling such a prominently user-facing (as in in your face) changes transparently enough?

There is a term, that in recent years my brain is using a lot when trying to explain to me what my eyes observe. Late-Roman Decadence. I am not a historian, so I might be inaccurate with its actual meaning. For me it just means "wasting because we can". If you want to see this in action, delete your YouTube cookies to get out of your tech bubble and open its start page.

Four workers arrive at a construction site to help. They each take a shovel and are eager to start shoveling. But what is that? They notice some dents and some dried cement on the shovels. So what now?

Worker 1

The first worker shrugs and starts shoveling. Better to work with 75% efficiency than not to work at all. Work needs to be done after all.

Worker 2

After two month in documentation I can tell you this: documentation in general is quite alive and kicking. :) From the outside you might see outdated content here and there, but there are quite a few people working on improving that. Of course, as most things, it is a never-ending effort and every helping hand is appreciated. If you are interested in helping, please talk to us on our mailing list.