A lot of people use motherboards with pci-e 2.0. I can't imagine that this wouldn't bottleneck people running those boards especially since most default to x8.

Like I said about tri-fire it'll probably also cause issues at pci-e 3.0 x4 like the Gigabyte UD5H (works great for 7970 trifire) and MSI Mpower. I don't see how this has any pros for the consumer.