When contesting the play the ball was allowed, it was rare to see a defensive line "on the back foot" or retreating as the attack moved forward, except from a line break. This was from a combination of the defense being closer, the play the balls being slower (from the contest causing more care, more policing of playing the ball correctly, and also less of a focus on play the ball speed from players) and players didn't all look like 100 m sprinters.
Now, getting the defense retreating is the main focus of the attack, and hence the play the ball and wrestling in the tackle the main focus of the game. It makes some parts of the game better to watch, and others not as good. But the game is definitely more end to end.
I like the idea of the game not focused as much on "winning the ruck battle" (i.e. speeding up the play the ball as the attack, and slowing it down as the defense) as it has been, and contested play the balls might help, but I agree with others here that the ruck is already too messy with modern techniques to add more confusion.
One on one tackles should be rewarded more than they are. For consistency, I'd like to see a timed limit to how long players can hold down in the tackle, so that wrestling, one-on-one tackles, knees in the ruck etc all are treated in the same way- the defenders can do whatever they like (other than hurt the attacker or steal possession) in the 5? or so seconds after a "held" call, and then any contact between defender and attacker is penalised. That way players can still get to marker if they make one on one tackles, and gang tacklers have to try to peel off each other in time.