South Stream isn't cancelled, it's only rerouted. Since the Trans-Balkan pipeline couldn't be built, the pipeline is being rerouted through Turkish Terretorial waters and will connect with the pipeline in Bulgaria.
A competitive Turkish pipeline, backed by the EU and US, is in the works but it's delayed due to a lack of funding. But the Turkey-Russia Joint Economic Commission says that's a non-issue so the Turkish section of the South Stream project can start virtually anytime. Greece also has a stake in the project and Serbia and Hungary are totally solid on completing the pipeline.
So tbh, I don't see anything standing in the way of South Stream now.
Turkey's new involvement in South Stream

Also, I totally agree that Russia diversifying it's pipeline routes and customers is the right thing to do. So even when South Stream is finished, the sales to non-Russian-Friendly countries should be considered a bonus and NOT reliable income.
It's never a good call to base an economy on unreliable "partners" (for gas, oil, or anything else - imports or exports).