While the basic intention behind access keys (to improve accessibility) is laudable, the concept is, in my opinion, fundamentally flawed. Essentially, there is no good way to implement it so that it's actually usable for the end user.

In order for access keys to actually be useful to the end user, the actual keys should be standardized across all websites. Otherwise, how are the end users supposed to know which keys they can use when browsing a particular Web Designer website?

Are you to encumber those users, and slow them even more, by forcing them to surf to an additional web page just to find out the list of access keys that are defined for that website? The additional step of going to a documentation page listing the access keys for the site is not worth the time. First, you got to search the entire page to discover the link to the access key document. Then you have to click that link to visit that page, read it and memorize the access keys available. What good does that do? You want to use access keys to save time, but you have to use a whole lot more time just to find out what the access key is.

So, in order to be useful, access keys need to be standardized across all websites. That way, users always know which keys are mapped to which page no matter which site they are at. Which brings us to the next (contradictory) point.