I'm of the firm belief that the on-field umpires have a critical role to play in this latest 'sling' tackle debate.
At the center of this debate is their want (or AFL mandate) to reduce the number of stoppages in favour of a more free flowing spectacle. I'm sure that many of you here will agree when I say that there are countless times during a game where we see a player being tackled by a vice-like grip that there's no easy means for them to dispose of the footy. How many times though do we see these umpires, almost lurking in some instances, in the hope that the ball will eventually come loose in order to keep the game flowing.
From a player's perspective (note that I've never played competitive aussie rule football, outside at school), the player being tackle would make every effort to try and break free in order to not be penalised for HTB, by the same token, the tackler would make every effort to prevent the player from releasing the ball, by every means possible in the hope of getting a HTB decision. Typically during this type of physical struggles between two elite sportsmen, the likelihood outcome is that the 'forces' will inevitably lead to them falling onto the ground. From there, you're pretty much entering a grey area with regards to how the fall took place, which part of the body took the fall, height/weight of the players involved, was the ground hard or soft, etc.
My suggestion would be for a directive to the umpires that they need to be more diligent in quickly blowing the whistle for a ball up when it's obvious that 'natural' ball movement has come to a halt. I believe that by applying some common sense into how these type of football acts are umpired, rather than religiously adhering to the mandate of fostering a free flowing spectacle would hopefully go a long way towards eradicating these type of contentious MRO judgements.