As XP increases in popularity and hits the mainstream, more and more teams will attempt XP, probably without a clear understanding of what is really involved. They will most likely be drawn in by XP's "low discipline" practices (such as no big up-front design and minimal documentation), but without applying the high discipline practices that act as an essential safety net (such as unit testing, pair programming, collective ownership and constant refactoring).
I know of one group who, when asked for the design documentation of their current project, replied "We don't have any documentation, we do XP". Needless to say they weren't really following any XP practices.
I suspect you need high-calibre motivated and disciplined developers to get XP to work and that development groups who struggle with more traditional development processes will struggle even more with XP. So examine why the current development process doesn't work well before jumping to XP. The same problems may well make XP even less effective.