If I were to develop a hardware for gamming I would put 3d ultra realistic graphics in second place. Off course HDR, displacement maps, radiosity and so on add to realism. But I'd invest more on particles, non pre computed animations, extremely efficent anti aliasing, texture compression, physic simulations, fog banks, sandstorms simulations, ice rain simulations, car damage, ripping cloths simulation, burning cloths, weting cloths, wetting hair, realtime volumetric liquids, so on.
I've understood some of the discussions in this forums, there are bottlenecks in MSAA + HDR (GF7 series inability to turn on both at the same time), vertex input bottlenecks, shaders bottlenecks, there are lots of bottlenecks here and there.