I think there should be a direct link to current and previous patch notes.
A good place for this would be under the "News" or "Wizard Society" sections of the main website. This would be easily accessed by players like the newsletter and message boards. There could be a running list of links so players can see what has been changed currently and in the past.
Though this makes me wonder... am I missing something? I just find myself digging for update notes every patch. I want it to be a little easier.