I think about $20 an hour is reasonable.
I understand people want wages for teachers etc to increase but their wages don't seem too bad to me. I was on 45k as a junior doctor and now 6 years out I'm on about $80k. But of course nobody jumps up and down for pay rises for doctors (but that's because we all drive ferraris of course lol). Most of the nurses earnt more than me despite me having all the responsibility if the s**t hit the fan.
I mean, who is going to pay for the huge pay rises? The taxpayers. Then everyone will whinge about that. Or how about big pay rises for CC workers? We will pay via the CC fees. And that means CC will be even more unaffordable.
$20 an hour for a tafe qualified worker seems fine to me.