One thing I hope the 6000 series can do (and I know it sounds petty but it couldn't hurt) is to shrink the length of the PCB. 5870 PCBs are larger than 480s, 5850 PCBs are significantly larger than 470s, and the 5830 is enormous compared to the 460. It seems like this could help out with smaller cases and cable management.
Also continue for power efficiency and low temperatures. They make fun of fermi but hey 58xx series cards can still get pretty hot under load. They aren't necessarily THAT much cooler to be throwing stones at nvidia like that
And the 460 has shown that GF104 can be extremely efficient. Definitely can thrash the 5830 (which has some serious downfalls for its performance category, like higher idle and load temps than a 5850) with lower idle and load temps.