I don't believe it's possible that any change to Outlook or any other mail software can significantly lessen the negative aspects of replies while still providing an initial copy of the whole previous message. This is counter to the argument some people have for initially positioning the cursor below the quoted text.

Maybe providing any original text is the problem here, but it's the lesser of evils in my opinion, because having no previous content would surely lead to issues for keeping on top of threads that weren't extremely recent or at the front of your mind.

I think the problem is simply the people writing the emails. At least with top-posting if you're reading a reply that's part of a recent (on your mind) thread you'll see the new information quickly, but the original email is there for reference should you slip a little. The same people that don't take care, or simply don't care, about replies would likely bottom post their whole messages. I would find it annoying as hell to have to scroll through unedited content ad-nauseam in reply after reply to get to the new text.

Personally I trim back quoted content judiciously and interleave my replies. Old/quoted text above new text. This is not a natural way of writing however for anything other than usenet/email, which is why people who have not always been exposed to this format won't be picking it up any time soon.

BTW, I remember people bottom posting well before Microsoft had even heard of the Internet.