I don't have any particular tenderness in my heart for ISO 8601, especially for things like:
"2015-08-02T21:50:49+03:00"
Who in the world is going to be able to understand this? Except you and maybe three other people?
"Ok, me, John, and Mary, and who is the third one", I hear you ask

The "Use English" setting is precisely for people whose phones are set to their national language, and yet they don't want this language to be used in quoting (because the other parti(ies) don't know it).
"US English" is apparently just fine for all these users -- just as long as it's "On ... August ... wrote" and not "... написал ... августа".
And so I have no intention to touch this at all, unless something truly serious surfaces up.