Ok, in my mind a question asked and not answered, so lets try and put it another way,
QUESTION: IS there a single post or white paper that bullet points the features and benifits of the NEW 4.5 Release?
My research could not find one, basically, it seems, you need to sort through the posts and piece it together yourself, I am afraid. If your are wondering if its worth the upgrade, its my understanding there were some security issues handled, especially in the Forum (Kudos to those folks for kicking that our so quikly). I am not sure if changes in security were made to the core.
It is also my understanding, but I havent had a chance to confirm this, that the 4.5 ships with the same text editor that we use in this forum, however , I think you may have to make a change in the webconfig file to enable it . This may only be for new installs updates maynot have this, wait I'll check.