Nvidia integrated graphics.
Intel would have to undo their current policy of forcing Sandy Bridge/Ivy Bridge CPUs to come with their integrated graphic solution and nVidia would need to jump back into the market. And considering how Intel's HD 3000 isn't that much worse then nVidia's Geforce 320M, I find it very unlikely that Intel's Ivy Bridge integrated graphic card won't beat the 320M.
Better GPU, with the ability to drive two external monitors at full resolution
I'm under the impression the GPU can already do that as my Mac mini has the same GPU as the 13'' model/high end 11.6" and it can drive the Thunderbolt Display and a 24" Cinema Display.(But the 999 model has the same GPU as the 599 Mac mini and that has a Thunderbolt and HDMI port, so I think even the low end MacBook Air can support it) but the issue is the Thunderbolt port doesn't support daisy chaining, so we'd need their the ability to Daisy Chain displays or more ideally another Thunderbolt port.
I'm hoping for
-Ivy Bridge i7 @ 1.8 GHz and 1.5Ghz
-Standard 4GB RAM / Maximun 8GB RAM
-Standard 128GB SSD on the low end 11.6"/13", 256 SSD on high end 11.6"/13" and 521GB as BTO all with increased read/write performance.
-(micro)SD card reader on 11" model
-2 Thunderbolt ports on 13" model and 1 Thunderbolt port on 11.6" both supporting daisy chaining
-USB 3.0(although I have my doubts Apple is going to implement this on any Mac)
-7 hour battery for 11.6"/10 hour battery for 13"
-HD camera
If we got the majority of those, I'd feel the urge to upgrade my 2010 Core 2 Duo model.