I would give a bright shiny nickel (or several) if Outlook (and other e-mail clients) would “learn” weighted rules for filters/folder sorting based on what I do. I.e., if I drag a message into a folder, it starts to figure out that messages with those characteristics should go into that folder. It would take a Bayesean learning curve (and there might be some feedback bits like, “I notice you just put this file here — check off the following conditions that would weight putting messages there in the future”), but ultimately it would be a lot easier than having to figure out rules on the fly, write them/modify them as we go, and then drag files around anyway.
It’s a dream I have.