What's wrong with the state of desktop GNU/Linux?
What's wrong with being traced back to the underlying window system, X.
Can Y be a modern windowing system?
The Y design has the following features, Mark Thomas says on http://www.y-windows.org/about.html
Network Transparency
Modularity (plug-in style: dynamically unloadable and reloadable)
Consistency and Themeability
Support for hardware acceleration
and
Better internationalisation, localisation, and accessiblity:
In-server widgets means there can be exactly one current language, one complex input method system for languages that require them, and one set of accessibility features.
This sounds good, but "one complex input method"??
The Y is not yet usable on a day-to-day basis.