KC - "moot", not "mute".
Goodbye to imports of note? The SEABL teams, on pretty slim budgets, manage to get imports, a number of who make it to the NBL. Who are imports of note anyway? No import in our league has any significant profile IMO. Ere plays for Nigeria but would be virtually unknown outside of the NBL. Same with Dave Thomas. A few might remember Rick Rickert as 'the guy KG punched', but what else?
The top tier would keep all of these guys and potentially more. The second tier would keep getting the cheaper starting imports like Rychart, Ballinger, Redhage, Gruber looking for an opportunity to prove themselves.
If it was carefully planned and managed, I don't think it would be the death of the league at all. And it's certainly not going to mean a guaranteed loss of major sponsorships and TV coverage hopes.
If anything, someone like Fox will favour covering a top league playing only out of the larger cities. And more regional teams in the second league will increase the potential sponsorship base - regional companies with not much else to sponsor in places like Darwin, Cairns and Hobart.
You mention that the goal of BA should heavily favour grass roots basketball, but the sport is already very strong at that level. I agree that the focus should not just be on the Boomers/Opals, and that leaves the NBL and WNBL.