Comment 6 for bug 953489

The best time to make this change would have been 2004 or so. Now it's just a waste of everyone's time. Even if a project author thinks it's a good idea and wants to use it, they have to wait until their favorite implementation is using a sufficiently-recent ASDF to make it work, and then they have to wait until all their users have upgraded their implementations, too. Unless you want to write a system like this:

(asdf:defsystem foo
  #+asdf-has-homepage :homepage #+asdf-has-homepage "www.xach.com")

Nasty.

Just stick with :properties.