As part of my day job at the Migration Council Australia, I recently helped author a submission into the current 457 visa enquiry.
The submission can be found here, noting it is a sizeable PDF: http://www.migrationcouncil.org.au/assets/files/f700eb611.pdf
The submission argues for higher program fees to fund additional support services for migrants and additional support for Australian apprenticeships. A higher program fee will also act as a better price signal for employers to maintain established wages and conditions. Current fees are $330 per visa. The submission advocates raising this to $1,000.
Other arguments include; the abolition of labour market testing, increasing program transparency, improved salary matching to Australian wages, the retention of a salary threshold, adjustment of English proficiency requirements and better monitoring and compliance activities.
There is a short appendix containing some data from a 2012 survey of the 457 visa program.
Other submissions into the enquiry can be found here (noting that not all submissions have been published to date).
For my personal opinion, this piece in Inside Story reflects my thoughts on the 457 visa program.