One aspect that I appreciate (at least theoretically; I run Debian Sid) about Ubuntu (and its K- and Edu- sisters) is the completeness of the system install: most users don't want to choose between the XFree86 and X.Org, for example. Let the advanced users worry about specialized configurations, rather than leaving it up to everyone to make each choice. And newer machines have enough disk space that installing a "complete" set of libraries and system tools isn't an issue.

If we were further willing to "version" those libraries (i.e. in the file tree, not just within the libraries), we might be able to let applications compile against newer libraries without affecting which version of each particular library other applications used. (And tracking the reverse links could allow an eventual trimming of the library versions. I'd like to see improved support for such capabilities in the file system, but that might cause additional problems, especially in the near term.)

As for kernel upgrades, I have never understood why the "default" binary driver packages didn't simply do the compile and install within the installation script, rather than making me execute such a script manually, line by line - often needing to consult pieces of multiple diverse sources where a script could determine the environment automatically.