What Is Linux Missing?

Linux is still missing "enterprise-level" features, such as journaling file systems, and suffers from non-optimal SMP support.

There is yet no standard GUI that will compete with that found in client operating systems (WinXX, MacOS), thought that's being worked on (KDE's KOM, GNOME).

Lack in commercial-quality (trivial install, "idiot-proof") general purpose applications.

Foreign languages support (using Unicode as a standard, support for BIDI languages), more standardized eastern-languages support (Chinese, Japanese).