There has been a lot of discussion that WordPress is becoming less user friendly and indeed it has got some traction as the recent WordPress 3.8 is certainly aimed (amongst other things) around making the dashboard more user friendly. Given this I don’t think wordpress is becoming less user friendly, however it’s never been friendly to newbies.
Instead I think the area where Worpress has dropped the ball is that sensible projects that could make its so much better are not being tackled, instead development seems to be based on UI improvements and quick wins. These are great but a better WordPress platform would make these sort of improvements easier. Indeed a better platform would enable people to build their own UI. Thus rendering the rolling MP6 (and similar initiatives) into the core moot (because developers would be rolling their own version of the dashboard through plugins).
Things like backpress, post to post relationships in core, or cleaning up the ridiculous wp db schema are not being tackled. These projects would make wp a better cms AND a better blogging engine. But they are not on the roadmap.
You can bet wp’s competitors are tacklings these sort of issues