First things first, thanks for bringing renewed attention to this!
We can all agree updating the treasury wallet multi-sig needs to happen. Looks like there are supposed to be Index 2.0 workshops dedicated to the topic per Index 2.0: Autonomy Next Steps 
Date* Workshop Theme Running workshop [8th September] Multi-sig signers and Treasury transition Process Financial and Administrative capabilities TWG, Funding Council
For decisions like this, we have seen that when all relevant information and perspectives are accounted for (using a tool for clarity like RAPID), buy-in is maximized & execution is smooth.
I think it makes sense to get a series of Index 2.0 workshops schedule to tackle this exciting topic.