I am not really a supporter of ongoing changes in super - I take the view don't trust present or future governments - of any political persuasion to leave it alone. It is far too big and too tempting as source of revenue that can be tapped to avoid making difficult real time decisions that may be more prominent in the eyes of marginal seat voters!
But, I don't necessarily think arguments around "have already paid tax on the contributions to their superfund" are that persuasive around this particular change. Yes, tax has been paid on those contributions - but even under these changes the original contributions won't be subject to any further taxation (at least until more changes are made by someone in the future :!
If I understand correctly, any earnings on someone's super "balance" (ie dividend and interest income + realised capital gains) over $100K will now be taxed at 15%. So to use a crude and over-simplified example, if you have a balance of $1m and realise 15% one year ($150K) - yet draw down nothing - you are liable for $7500 in tax - and your balance will only increase to $1,142,500 not $1,150,000 as it currently does. If you draw down $150K, your balance will end up at $992,500 instead of the $1m it would under current rules. If you have only 10% return (ie $100K), and draw down $150K, you will end up with $850K in your account under both old & new scenarios, and not pay any tax on either the $100k you earn in the account, or the $150K you draw down. Or am I interpreting this incorrectly?