You probably hate me by now, but here's another problem I found (my customers reported) to do with activation:
When content is activated, the lastAction is set to the publication date on the author system. Unfortunately this seems to happen after the content is sent to public instance.
The result is that the activated content on the public instance always has the "previous" value for the lastAction metadata field compared to the author system.
Content is first published on 15.4.2012
Content is published again on 15.5.2012
Now, on public system lastAction is 15.4.2012 while on author system lastAction is 15.5.2012
This means that after activation, content on author and public instances is different!
This is a problem for us, as we use the publication date to sort the content for various listing type displays.