What are the real world advantages of PCIe 3.0 compared to PCIe 2.x?
The actual answer to that question is: None. There are no "real world" advantages, hardware/spec fanboys just want it for e-peen bragging rights on big numbers. Nothing uses the bandwidth of PCIe 3.0, maybe some giant quad processor Tesla board or other supercomputing accelerator. Nothing exists really that even supports it yet. As of the launch of SNB-E, there will be no reason for it. Probably why intel didn't bother to include it.