I've been thinking of writing apt-listreadme. It is basically the same as apt-listchanges, but it would list readmes instead of the changelogs. So it would have to extract both debian and upstream's readmes (obviusly this could be configured), display them (through less, a web browser) and/or mail them to someone. I have to consider also if it makes sense to write a new program instead of adding to apt-listchanges (which seems much more logical).
The idea is that whenever installing *new* packages, the readme should be shown, as I usually never read them and it is useful to read them. Obviously they shouldn't be displayed when upgrading or reinstalling a package.