I think quality should be the focus in any of the domestic competitions. I don't like the idea of making a league into a young man's game just because some cbf playing it well or having a policy of only picking home-grown players because of pride. There are plenty of competitions in which to develop young or up-and-coming players. As great as it is to watch young stars in the making, it is only a reckless indulgence to persist with them when they are not ready. It does nothing for the competition and does nothing for the players they compete against.
Australian Twenty20 was always going to get more serious. There was no way to get less serious than the Andrew Johns stunt. IPL means there is incentive for individual players to catch the eye and win a lucrative contract. With the lure of the Champions League, there is merit for individual states to up the ante. Then of course there is the national interest and currently the Australian cricket team is known for two things, playing badly against spin and losing at Twenty20.
For the most part, the state boards have been rather tame in their signings. Even when McCullum was signed by NSW in the middle of the tournament, at the time seen as so incredibly indecent and dishonourable, the end result was relatively insignificant. I don't believe that it is ostensibly possible for the teams to abuse their paltry 50k bonus and two player cap. The laws simply don't allow for Kolpak style deals. If a better competition is achieved, then there ought to be benefits for everyone around it. Even fringe players will train regularly with their new teammates. In the case of an elite spinner, such an experience could be a great boon to a player hoping to charm a selector... such as David Boon.
It may cost a small number of players a spot, albeit one they might not even have been assured of in the first place, but the players who actually make the XIs (of which, many will still be quite young) will benefit a great deal from a stronger competition.