The more I think about this the more I think the Federal government should not be involved with this at all.
Australians love sport and there is always call on the Federal Government to fund stadiums. To me I would now put a limitation of all investments in stadiums over say 12,000 capacity - whether it is oval or rectangular.
Think about it. The government is constantly asked to fund stadiums for cricket, AFL, football, rugby league and rugby union as well as for concerts and community events. Why?
If you want a new stadium or you want a change to an existing stadium then it should be funded once and for all, ideally as part of a urban revitalization project. I'm not talking ovals, I'm talking real convertible stadiums that can change from rectangular to oval or back again in a timely manner. Sure it will add costs to start with - but it will mean that there won't be multiple costly stadiums servicing multiple sports when in reality most major cities need a smallish (20,000) medium (45,000) and large (65,000) type stadium. Now it might not work on every footprint. i.e. Hindmarsh can't be expandable to an oval because the footprint won't allow it.
Secondly, if you want government federal government funding you should no longer control scheduling of the ground. i.e. you can't accept money and then lock out other sports. The money is the taxpayers, not a sporting bodies. If they want to control - they can pay for it.