As an expat Aussie, current 777 TRI, with a CASA Licence that says 777/787, unless JQ offered a package significantly better than what their 330 SIN offer was, I wouldn't consider it. But then, what would I know, I'm not ex Ansett so probably can't really fly anyway!
FWIW though I do personally believe seniority benefits the employers over the employees as it gives a captive workforce. If the experience isn't 'in house' then there should be an option to employ outside of seniority (and I spent nearly 10 years in the RHS!).