"the whole production of the NBL broadcast needs an overhaul."
The starting point should be the work that happens away from teh microphones. The research into players (backgrounds, human interest stories, past exploits, season/stats to date, etc.), teams (who's on the bench, season performance/stats to date, record at the venue, etc.), coaches (as for players, include assistants and other staff - there are often gems in support staff's histories, tactical preferences, coaching styles, etc), crowds (locating human interest stories in the spectators that might be worth running (get them from the host clubs and use them if they're worth it).
The review all that research output and put together a broadcast plan for the game that allows you to fill dead time with informed. hopefully interesting material rather than just filling it with stream of consciousness babble. This sort of research, plus intelligent application of the results, are what distinguishes the excellent commentators.
The other stuff that happens away from the microphone is the camerawork, production and support staff. The statisticians who feed useful data to the commentators; the directors and video staff picking the replays and cutting them in at the right times, to support the commentary, not to stymie it; the different camera angles etc.
As far as I can tell, NBL is on a budget that doesn't allow for any of the above to be done well. i.e., commentators woudl only be paid to call the games, not to do the research; only a couple of cameras per game; no stat person to feed stuff to the commentary team etc.
So you're left with commentators relying on existing (necessarily personal) knowledge and experience, with little or no control over replays and access to stats. The result is whatever comes into their heads, peppered with anecdotes, inter-commentator banter and repetition.
Add to that the fact that the commentators are watching the game remotely, on a screen. They have no broader view of the court, stadium and crowd. So they can't feel the atmosphere nor can they talk about off the ball and off the court stuff that doesn't get camera time.
Any commentator who can come across as half way interesting and not overly repetitious in that setting, is doing well.