A tiny modification that could be a big step in a useful direction.
I'm not an Outlook user, it may seem contradictory but that's exactly
why I'm writing this. Since it's part of MSWindows, Outlook is the most
widely used MUA out there, hence everyone, both those who use it and those
who don't, has to deal with its default behavior. Among many other
details I could mention, I'll limit myself to talk about the most annoying
one: half of all the disk space in the world is filled with Outlook
"Original Message"s piled at the bottom of replies as garbage. I bet no
Outlook user ever put any use to that text.
So, appealing to your understanding I am going to suggest a tiny
modification in the way Outlook replies: to change the MS historical
"Original Message" line by a more functional one (eg. "On Sat, Nov 05 John
Doe wrote:") and quoting the following text with the widely used '> '
prefix. That way, at least, you will give those who know how to
efficiently follow a dialogue in a thread the opportunity to put that text
to some use. Most Outlook users won't even notice the change, it will
mean no harm to them.
I know that Outlook includes that option in its configuration but, let's
be realistic, most people limit themselves to accept things as they are
sold. And I'm not able to change the habits of many as Microsoft is.