The new XCode 4.2 and presumably the next versions of it do not ship with a real GCC, which is one of the things mentioned in the article.

This causes problems for software that doesn't compile right with LLVM yet (arguably bugs in the software, but tell that to someone who can't use the LLVM compiled binaries any more).

Eventually, the version of Xcode that includes GCC will be too old to do anything useful with.

So then you wouldn't be able to "just install XCode", unfortunately.