What's wrong with the way it is now?
The NBA is a league of haves and have-nots. Not all of the "haves" are big market teams, but small market "haves" can very quickly become "have-nots" when their star players leave for nothing, or force a trade. Small market teams are faced with a choice between spending beyond their means to compete or not spending and never making it past the first round. It's too easy for players to work hard to land their first big contract and then take it easy after they've been paid; other players suffer injuries that severely limit their productivity, making their contracts dead weight. Yet since the contracts are guaranteed, their teams are saddled with the dead weight.
I could go on.
Yeah, I just don't think Basketball is a sport (at least with 30 teams) where you can have a system that has teams working with such dramatically different financial resources. The sport is just way too reliant on top end players.
Especially since the rookie salary system is set up so young guys get paid big time money just 3-4 years after being drafted, and in many cases, the first year or two of that they are not really ready to compete at the top levels (as compared to baseball, where players will not be brought to the big leagues until they are ready, and their 6 year clock does not start rolling until they make it to the bigs).
So, essentially, teams get 1-2 years of affordable play on rookie contracts, and then they have to pay the guys dramatically more money. And this really does prevent most small market teams from any sustained success, and creates a situation where they are forced to either overpay these guys to keep them, and then put themselves in a tough position cap-wise, or let them go, alienate fans, and become an even smaller market team, starting from scratch again.
This BTW is also the argument for raising the age of eligibility for the draft. If guys are coming in at 20 instead of 19, then perhaps the 1-2 years of quality basketball on a rookie contract becomes 2-3 years, because players will be further along in their development (on average) when they enter the league.