desu

This behaviour sounds perfectly reasonable for the common case, for whom it was designed.

Furthermore it sounds like this guy is using Time Machine as an archiving solution, not a backup solution. You shouldn't be all that worried to lose backups a year old if you know newer ones are intact. You should never delete a document there's any chance of ever needing again, then rely on TM or similar to save it for you.

I think the single best thing you can do with wordpress is to run an SVN install. They're usually pretty good about tagging updates, so for example the update to 2.8.4 consisted of this:

  svn sw http://svn.automattic.com/wordpress/tags/2.8.4

Which is about the acceptable level of hassle IMO. Much more and I'd be outta there.