I have been thinking about that also, trying not to re-stock woods of which I know they are problematic. But I admit, I never made a very concentrated effort to educate myself about it, I was rather thinking to focus more and more on sustainable local Hawaiian woods. I did not know, for example, that African blackwood might be getting scarce. I got mine from people who - according to their info - have family connections to an African country and don't do this on a large scale, and I decided to believe that. Koa is, as far as I know, not such a big issue. Clearly, they harvested too much in the past, that's why there are restrictions to only harvest fallen trees at this time. But it gets replanted a lot and is not rare as such, just that there are not too many really old trees left, a generational gap, so to speak. But I am not a forrestry person, so I would not bet on this...
There would definitely be woods I would miss if I limited it to Hawaiian woods, although a limit to US woods would still give a nice and large range. For me, one of the joys it to experience all the varieties and try to be creative with them. But I may rethink this and narrow down my range. Easier to limit it to a few reliable sources also. We'll see, not yet sure where the whole woodworking thing will be going anyway.
Stefan