...the BRICS currency could depreciate the US dollar.
Like I said, there is no plan to create a unique BRICS currency. They will just start to use each other's currencies
also: China has strict monetary controls, you can't take your Yuan out of China for instance, so they will not allow for a BRICS currency that they can't have similar control over.
BRICS don't vote like the UN does, they all have the same "vote" (one) and no country has more "say" than another. They also don't have a veto like the UN does.
I also believe that they should keep their economy and domestic currency under tight control. The world will witness a pleasant environment if every alliance and state of the world has a spirit of cooperation and efforts toward development.
Experts have debated the currencys hegemony and being perceived as a geopolitical rival of the G-7 due to various BRICS initiatives such as the New Development Bank BRICS Contingent Reserve Arrangement etc. I believe that other like-minded countries including the countries included in the BRICS alliance will benefit if they remain free from that aspect.