Rolling the player in the tackle is often called a dangerous tackle, you just can't win. I don't reckon we push in the back more when tackling, way too many players these days just fall forward in a tackle to get a free, it is a blight on the game and they need to stop giving free kicks when it happens.
On the second one, the over the shoulder tackles, I agree we haven't learned well enough to avoid the shoulders and the way players shrug their arms or duck for a free. I would add that I've seen plenty of instances where a Richmond player has been tackled on or over the shoulder and no free kick our way.
DS