Prior opportunity is the entire problem.
Prior to Tim Lane deciding it should be a thing, it wasn't. Players would sense they would be tackled if they took possession and instead knocked or paddled the ball on (see Baldock, Bartlett). In a time when the AFL is trying to cut down on stoppages prior opportunity allows players to force one almost at will. Back when the game was adjudicated properly, a ball-up was the result of a stalemate - when two or more players were fighting for the ball and none could win it, like a basketball jump-ball. Now, a player can 'accept' the tackle, or furiously punch the ball into his armpit and be rewarded with something we don't want, while the players in a stalemate must give up and let go of the ball lest they be pinged for daring to try to win a battle for possession.
1. If a player takes possession, is tackled, and does not dispose of the ball, pay holding the ball. No prior? Who cares.
2. If a player takes possession, is tackled, and attempts to dispose of the ball - and it comes free (e.g. tries to kick and misses his boot), call play on.
3. If a player takes possession, is tackled, and throws or simply drops the ball, pay illegal disposal.
4. If a player is pre-emptively tackled before he takes possession, pay holding the man.
It's such an obvious, logical, traditional way to address congestion - no wonder the AFL can't see it.
I'd even be happy to roll 2. into 3. and insist a tackled player must dispose of the ball correctly if it eliminates grey areas and controversy.