With as recent a POD as possible, make Swiss-style square flags universal. I wouldn't have any clue how to get this result, but I'm curious to hear any ideas. We must have some flag experts around here.
Then they wouldn't be flags.Sure, if the point of a flag is to flap in the breeze, it makes sense for it to be longer than it is tall. But what if the point was more to serve as a shield, or be mounted on a flat surface? Or what if Roman-style standards were retained into the modern era?