First off, Shanghai and Warsaw are two very different cities, and because of that I think the SCO is a different animal than the Warsaw Pact. For one thing (aside from the difference in the two cities, one being selected for its geographical prominence, the other for its commercial acumen), the Warsaw Pact was a military alliance led by the Soviet Union, while the SCO is dedicated to political and economic cooperation as well as military security. Notably, the security aspect of the SCO is dedicated to coordinating state-led efforts against terrorism and separatism rather than against a rival alliance.
I don’t see anything wrong with multilateral efforts undertaken by states other than the US. I don’t see any need to worry, fret, or otherwise suspect the SCO of undermining world peace and prosperity. The fact that the SCO is made up of cooperating autocratic regimes rather than democratic ones does not faze me. The SCO has been making overtures to the democracies of India, Iran, and Sri Lanka (be sure to check out Tridivesh’s excellent take on India and the SCO), and multilateral cooperation among states is in itself an exercise in political participation among equals, albeit not at an individual level.
There is also cause to be happy that China and Russia have bound themselves up in such a prominent cooperative venture, too, given the two powers’ history of fighting each other. The SCO is contributing to peace and prosperity, and while it appears on the surface that the venture is designed to be a rival of the Western-built world order, the Shanghai Cooperation Organization actually contributes to it.