Re: rounding of wear, maybe it isn't wear and it's just the flow of the metal on a worn die?
Which brings me to my next question: since the dies for many of these medals and coins didn't have long lives, what errors and varieties that we see in modern (think late 1800s US) coins won't exist on dies with short lives?
In other words, since heath care and veterinary care is so good these days, we're seeing new diseases and complications because humans/pets have never lived this long before! What "diseases and complications" are not seen on short lived dies?