Not every ten years, but I think a big one-time redraw would be great. We don't need two Dakotas and even if we did, it should be East/West instead of North/South.
https://xkcd.com/1902/
Alt text: A schism between the pro-panhandle and anti-panhandle factions eventually led to war, but both sides spent too much time working on their flag designs to actually do much fighting.
Alt text: A schism between the pro-panhandle and anti-panhandle factions eventually led to war, but both sides spent too much time working on their flag designs to actually do much fighting.