However there is now a no-warrant-required method of getting information (in the form of TANs and TARs) which has no judicial overview -- previously they would've needed a warrant. This is definitely a massive concern, but given that you wouldn't have seen a warrant previously (Fastmail would get it) this is not a practical difference to you (obviously it's a massive ethical difference and so on).
But to be honest, I actually hope people stop using Australian services and big companies start backing out of the Australian market. It's the only way our dropkick government will realise how much of an own-goal this legislation was.