Umm, forgive me for being picky, but I fail to see anything better, or for that matter, worse, between:
A5 is 5.83 x 8.26 inches
A4 is 8.26 x 11.69 inches
A4 is 210 x 297 mm
Letter is 216 x 279 mm
Now, if A4 was 200x300 mm, there might be something to crow about!
And, yes, I do know that the ISO paper sizes are metric with the aspect ratio based on the square root of 2 so that each sheet is exactly half the size of the previous one and that the actual area of the paper has a nice, round metric value.
I just love to argu...um...er...debate issues!