The current AMD Radeon HD 6750M (40 nm), as found in the better of the 2011 15" MBPs:
- is extremely power hungry: battery life basically halved when active
- runs super hot: raises to 60-80°C just by plugging in an external display with no 3D or H.264 decoding, plain desktop. That wouldn't be a problem in itself if not for the fact that its heatsink is connected to the same heatpipe as the CPU's, so a raise in temperature in either, raises that of both. As a result, the CPU runs hotter when the 6750M is active.
So, hopefully they won't be greedy on performance with the new 28 nm and keep similar performance levels as current mobile GPUs, but at (way) better temperatures and power requirements.
6750m "sips" 30-35 watts at peak performance. This has been the standard for over 4 years now. A step down to the 540m, you get the same 30w usage. You'd have to go all the way down to IGP levels of performance to see a dramatic drop, to about ~20w for the 520m. However, the next step up, the 560m is rated at 75w, and the king of the hill 580m uses 100w.
The reason why this is so is because the ATI/Nvidia feel like they can satisfy the "battery/eco" side of the consumers with their graphics switching capability, and just pump out more power for the other users. Makes sense. I wouldn't expect TDP to drop at all.
Still doubting 2011 update. Macs just aren't the priority they use to be, at ~20% of Apple's revenue.
I do dearly hope they keep on producing 16:10 laptops, and not conforming to the idiotic 16:9 resolutions that all PCs have adapted.
One wish that I doubt will be implemented is to remove the optical drive for a better cooling solution, as LG have done with their P3xx line. They're equally/even more thin than MBPs, the same performance, yet offer much better heat management because of this decision.