Ryan, read it again. I DO my own diffs. Most people can't or don't . If you think that the only people who modify the WordPress presentation layer, which is full of code that you might change to fix bugs, are also people who use CVS or Subversion and know how to diff and merge, you're sorely mistaken.
I don't need "such a detailed changelog"; as you point out, I can and do generate one myself. I need a basic idea of what changed. If you fixed security bugs in a handful of functions, in a couple of files, and dind't touch the presentation parts, I feel good about just updating those files, rather than blowing away my entire installation and painstakingly re-implementing all my customizations -- which is what your installation instrux tell users to do.
Since I know what I'm doing, I can ignore your crappy instrux and do the right thing. I'm asking you to give useful instructions for people who DON'T already know how to do the right thing, but who have found that they can hack the PHP, just as they used to do with HTML, and make some cool changes. Telling them to just blow away their site and install the new code is just wrong.
Macman's comment was actually helpful -- thank you, I can see some changes made in the last few hours, and some made months ago, so that gives me a good starting place to browse. Consider putting those instrux in the upgrade instrux.