Qantas is the third airline I have worked for. The first airline (a major European flag carrier) had an allocated 'fair share' rostering system. The second airline had a purely allocated rostering system but then progressed to a rotating seniority system. Finally now I work under a seniority based preferential rostering system. I personally find this the most archaic way of doing things in my 17 years as a Flight Attendant.
It is a system that may work if there is a continual turnover of crew and continuing full time recruitment. This isn't happening at Qantas and doesn't look likely too under the current management.
Yes there is expansion on the horizon - but that means recruitment of more casuals, more overseas based crew and more contractors, it isn't going to change relative seniority.
Your global seniority may move upwards, if and when all of these senior crew start retiring, but it doesn't mean much if the number of people below you on the list doesn't also increase.
The fact is - the grass is always greener, and i'm not advocating abandoning the system entirely. I am in favour however of tweaking the system so it's a little fairer to the majority of crew