It may sound a bit silly but I reckon the change from a leather ball to the modern, uniform Steeden is a factor in the change in both attack and defence patterns and methods. The Steeden is more strippable and more predictable in both passing and bounce. Ball handling, passing and ball security were more ‘variable’ back in the day and a legs tackle could more easily stop the progress of the ball in attack ie; one on one a great, grassing tackle could bring a player down ball and all; these days a legs tackle is more likely to enable the attacking player to get a pass away. Just my ‘old fella’ observations.
I still think the low legs tackle has been too heavily discounted in the modern game. It was a truism, and it still applies, ‘can’t run without legs’. I sometimes think it’s been forgotten how quickly a guy will hit the ground if his legs are well wrapped up.