Well, just for the info, Outlook 2013's Move menu has Actions, with Edit Message (and Recall, Resend, View in browser, Encoding, Header & View Source) in the drop down list. It also has an Editing group with Translate, Select and Find. Weird that Edit isn't there too, but that's MS for ya!
I have been using the ability to edit email for as long as I can remember which is why I would make the "basic" crack. But I only recently got a Samsung Note 4 and found out, with a little patience and attention to detail, I can seriously operate off it. Thanks in no small part to Aquamail Pro, so thank you Kostya for getting the best way to do this "out there". It is no small thing to get the subtleties you have built in, and I soon figured out that, despite some commendable efforts of others, Aquamail pro is unique in having got it right.
Would it be a big deal to make emails editable? I thought it would be a simple thing to do from my, admittedly limited, understanding of the mechanisms involved.
Apart from the earlier stated use of email editing the other thing I sometimes do is correct important errors in earlier chain emails and highlight it and reference the change in later text. You don't want these kind of errors lying around for people to read without finding the later erratum as they can stuff things up a beauty. That can be done no worries with Aquamail. It is just the straight file it jobbie I would like to be able to influence. But I have a workaround, albeit cludgy, so no drama...