The other banks will be watching the reaction to ANZ changes. In any case, there is no joining fee (like Diners) for Altitude card, just the annual fee. So, even if westpac changes the annual fees after you have joined, you are already a winner by saving the difference between ANZ and Westpac at least for an year. Looking at the past, ANZ has always charged higher fees. But those days, the bonus points were extreely generous especially with Telstra.
Only inconvenience is changing direct debits to your credit card. But, considering the savings, it is really minor.
Let ANZ know that you don't like their fee increase by CANCELLING their card.