In the Linux world more so than anywhere else, you have an odd and "at-odds" mix of users. There exists the "1993 was a great year for Linux" crowd, and the "Linux on the desktop" crowd. And somehow, you have major overlap between the two. While there are distros and packages contributing to both mindsets (meaning the two can coexist just fine), the biggest problem I see in the Linux world is the users who outright reject experimentation and change.
Personally I love where Gnome and KDE (and even Unity) are going. I might not use them daily, I might not find all their features helpful or productive, and I sure as hell am not using them on my server, but there is nothing preventing any Linux user from simply not using the new software. It's easy to find a distro that uses Gnome 2 or KDE 3 or doesn't have PulseAudio. But it's hard to use modern day software without modern day packages or backends. Without this rote experimentation that is at the heart of open source, I wouldn't be using Linux on my desktop. There are a lot of very controversial ideas put forth in the mainstream distros over the years which have contributed more to the adoption of Linux than they've taken away from the traditional users.
If someone doesn't like Unity, doesn't like Gnome 3, doesn't like KDE Plasma, doesn't like bleeding-edge distributions... there is a choice. Debian, Slackware, Arch, Gentoo, the list goes on. I don't much like the interface of OSX, but I don't create mailing lists to pooh-pooh it, I simply don't use it. If you have a point, make it. If you just want to complain, get a cat.
KDE - mostly fine, I use it, but it still won't let me set a default transparency the way I could in v3.5. If I could find a supported way to run 3.5 I would.
Gnome/xfce - gtk-based so backwards button order, requires magic typing to let you enter a file path in an open dialog, probably other things that would annoy me if I put up with those any longer. Gnome also has registry-based configuration, and neither has a decent well-integrated browser or email client; firefox/thunderbird/evolution work as standalone apps but e.g. drag-and-drop doesn't work as reliably as on KDE (or didn't when last I tried), proxy settings have to be configured individually, etc.
xmonad - urgh. Underdocumented if you don't want to learn haskell, and doesn't even have a browser etc. last I looked.
There's not a whole lot wrong with KDE, but for my use cases it's still worse than it was on version 3.5 (the aforementioned transparency problem, and the lack of a music player with the features of amarok 1.4 are my main issues). That's the most irritating part.
Personally I love where Gnome and KDE (and even Unity) are going. I might not use them daily, I might not find all their features helpful or productive, and I sure as hell am not using them on my server, but there is nothing preventing any Linux user from simply not using the new software. It's easy to find a distro that uses Gnome 2 or KDE 3 or doesn't have PulseAudio. But it's hard to use modern day software without modern day packages or backends. Without this rote experimentation that is at the heart of open source, I wouldn't be using Linux on my desktop. There are a lot of very controversial ideas put forth in the mainstream distros over the years which have contributed more to the adoption of Linux than they've taken away from the traditional users.
If someone doesn't like Unity, doesn't like Gnome 3, doesn't like KDE Plasma, doesn't like bleeding-edge distributions... there is a choice. Debian, Slackware, Arch, Gentoo, the list goes on. I don't much like the interface of OSX, but I don't create mailing lists to pooh-pooh it, I simply don't use it. If you have a point, make it. If you just want to complain, get a cat.