Sandy bridge, nvidia integrated and discrete graphics with auto switching, larger SSD? the superdrive will remain, longer battery life, lightpeak, bigger trackpads, possible screen resolution increase but doubt it.
Apple will absolutely not offer a dual hdd setup I think. The chassis design will remain the same as it is.
bigger trackpads? Don't know about you, but my trackpad is bigger than just about any other laptop trackpad on the market... You mean you want a trackpad even bigger than that?