In a small market such as Australia the no seniority rule would destroy the career progression of pilots as it would open up direct entry commands to anyone in the world who has Australian Citizenship or residency. Given that Australia is a favourable place to live, people from all over the world will be shafting each other to get a command. The companies will love it as they will get people with command time on type minimal training required and plenty of people will put in low ball bids just to be able to fly in Australia. Expats can afford a low salary as they are already cashed up, people escaping less favourable countries will be more than happy to take low pay just to live in a safe secure environment. You will then get someone in a management position who will then want all his mates as captains and without seniority there will be plenty of jobs for the boys. As I said above it will create the situation where to qualify for a command you have to spend years in some exotic location just to get the minimums to qualify for a command.
It will be GA all over again.