As the rules stand, a player can only be re-rated at the end of a season. I would find it incredibly suspicious if an import player, (and everyone in the league knows, quality aside, a restricted player is an automatic 10pt player in this league) is re-rated down two points mid-season just so a team, ANY team, no matter if they're coming first or last, can fit them in, especially, due to other teams folding, there are other players available.
If he gains Australian citizenship, those rules then don't apply to him, so if he's re-rated based on his new status while currently unsigned, then fine...
Changing the rules mid-season shouldn't happen... Hopefully this forces the NBL to review procedures and they can let teams know that changes are afoot so that they can recruit based on these new/amended rules, not wait the whole off-season and then the new rules come in when all the teams have been filled...