Given that the rule is supposed to be that a player must make an immediate attempt to dispose of the ball (prior opportunity or not), a 360 (when their arms are free or mostly free) is clearly not an "immediate" attempt, but instead waiting for an opportunity to choose where they dispose it to.
As for the sling tackle - I agree that it's getting out of hand as to what is / isn't a dangerous tackle, but at the same time I can understand the desire to get it it (slamming the player to the ground with consequent risk of head knock) out of the game. As Brasher says, if players are given too long to dispose, then there's an incentive to bring them to ground.
However - as I recall from back in the day, the ideal tackling technique was to wrap the player up and then drop your knees, thus forcing them down - and even if the player is strong enough to stay standing while there's 100kg of opponent pulling them down, well, then, the key is in the wrapping up. I dunno - maybe if that was the preferred tackle, slinging to the ground wouldn't be so necessary.
Did we see players being slung to the ground in the tackle, back in the dim dark past? I don't know...
