One of Australia's strengths is our small domestic competition which compounds the talent and leads to a far higher level of competition. This prepares cricketers for Test cricket better than any domestic competition in the world. Plus, the constant pressure of losing your spot sorts the wheat from the chaff. You're put under pressure at a very young age, and if you overcome it and score runs under such pressure, you have shown that you are capable of scoring under pressure, which is vital in Test situations.
I don't see the need to expand our competition at the top level, but someone mentioned expanding the Second XI level, and that's something I definitely agree with. Each side only plays 2 matches a year in the CA Cup, and that simply isn't enough....There needs to be more 'formalised' and more 'professional' cricket played at a level lower than Shield.
Not that I think there is much wrong with our set up at the moment. It's easily the best in the world....I don't see any need for radical change.