IMO, WCAG2 needs to be viewed with caution; it isn't a panacea thet will ensure maximum accessibity. In some cases sticking tightly to WCAG specs may damage accessibility.
This is largely a result, of course, of progress made since these specs were drafted. Let's not forget WCAG2 took 5 years(!!) to draft and was published in 2006. A *lot* of progress has been made in the intervening 10 years and the web, and technologies used to interact with it, are very different than they were 10 years ago.
Yes, it is the best we have in terms of spec, but that doesn't mean we can't do better