It's all about Russia and China trying to increase their influence in the world through the arrangement of third world nations against first world countries which are lead by USA. I don't know how strong this economical alliance can be, but I fear we get more distant from US and their allies to give preference to russians and chineses. Living in Brazil, personally, I prefer to stay with the occident, because it's still where freedom and individual rights are more respected than in the rest of the world. And if BRICS get stronger, I believe there is a real threat tyranical practices from the east may be applied to us too, even living in an western country.
That is a trouble even right now, and the fact that they could grow to be bigger is definitely scare for sure. However, I do not think that they will get more powerful, they still need the money from the west, all these nations are poor compared to west, only nation in all this list that could be considered rich is China and even they are having financial breakdown right now, USA could crash as much as they want and still come out on top and that is what matters.
I believe that we need to end up with a situation that is a bit different and should be considered that BRICS could never be rich and just need money from the west all the time, they need to sell their resources, factories, workers, and everything else just to get money from the west.