Hi SB
all the animals you mentioned were imported long before anyone had any idea of their impact on Aussie wildlife. It's never too late to start doing things right (whatever that means). I know that if I started finding some kind of exotic snake outcompeting the Diamonds or RBBS on my property I would be really P*ssed off not matter how nice they were. It's easy to stuff things up and I live where I live 'cos I like the way it is. So my vote is they should never be legal - well not until there is a foolproof way of ensuring that they cannot breed - That reminds me of Jurassic Park.