It's simple - but incredibly hard to adjudicate.
As the impact is generally very minor - why not simplify it?
The rule is fine. It rewards clean marks. And punishes players for not cleanly marking the ball if they are near to the boundary line as they collect the ball. Never had a problem with it. Sure there's a few iffy decisions on it now and again, but it's not prolific like the HTB / incorrect disposal / prior opportunity / holding the man shit show from last night. They paid HTB when players had no prior, they paid holding the man instead of HTB or incorrect disposal when players were tackled with the ball and had prior. It's just a mess as to how each contest is going to be adjudicated, whereas it's very clear how a juggled mark is adjudicated.