Brazil, Indonesia and S Africa are not problem nations for the US and the West, I believe, because they are important nations in nascent unions like the UNASUR, ASEAN and African Union, all US and Western allies. But China and India are future threats, so there is a fundamental difference about these two nations. China and India's increasing assertiveness in world geopolitics will convince the US and the West that these two nations with 4 times the population of US, will become their nemesis, so plans will be made to tackle them probably via some kind of changed trade regime. WTO based neo-liberal free trade may not continue for very long, as it is hurting the West, so they may change the rules of the game, to bring things in their favor, which may hurt both China and India, but not other smaller nations, since all of them are allies in different regions. So expect manufacturing to slowly move out of China and outsourcing to move out of India. I could be wrong, but I see US public opinion very hostile to China and India, because they are stealing jobs and prosperity and now with the new Chinese aircraft carrier surfacing, everyone is talking about a China threat and India is another China, just 15-20 years behind, if not more, so both might be tackled at once.
Attacking Iran is one thing that the West is definitely not thinking of, because Iran is not Iraq or Afghanistan and both of those places drained the West, but burning Iran's hand in Syria would be a peace of cake and a nice little game for the West and Israel. It may be a little destabilizing, but really nothing serious, I think. If anything it will strengthen Iraqi Sunni hand, who might take part in the Syrian melee and thus Sunni's will even stop their violence in Iraq. So there is many regional angles to this brewing conflict. Assad has a big Alawi army but there are many Sunni soldiers who may defect and unfortunately this will turn into sectarian war. Assad dug this grave for his entire Alawi clan to go down unfortunately, it will be ugly. Syrian Sunni's are not going to give up at any cost, specially after Libya. They are ready to die, whether they die demonstrating or fighting back, makes no difference to them any more.
About financial problems and imperialism of the West, I think for us little nations, Muslims or otherwise, it will be better to stay in the Western camp, China and India may want to become new imperial masters, but we in Bangladesh already know what it tastes like, believe me its not good. For me, I would rather see that West and Russia get together and give a good beating to China and India, while help the rest of us become strong and united in different regional groups.