If I want to find out what has changed in 1.4.2.4 I get a link to the trac page listing all changelogs ever. This is lazy and arrogant, each release should have its own changelog explaining what functionality or features have changed (and preferably why).

Well, I don't know if it is "arrogant" as most people won't read that anyway. You could use an svn client to view the changes. They are publicy viewable. Trac is not able to create such.

I could generate a pdf with the changes but that would be for sure several pages. We actually plan to do that from 1.4.3 on. To tell documentated what changed why is really out of possiblity besides Trac tickets and the actual svn comments.

Addition: On minor releases like 1.x.x.x features don't change and also no major ones are added at all. Compare the 1.4.3 release post that is already linked in the beta release post.