I love the idea of 16 a side, I think what the worry is that teams will play a chip, chip, chip style because they will be too worried about getting burnt on turnovers.
I think a few country leagues reserves now play 16 a side.
I agree that’s a risk, I say make it 20 metres or even 25 for a mark to make that style very difficult. And / or no longer rewarding a backwards kick with a mark except in forward 50