Remember, the Ivy Bridge and Haswell chips will run a lot cooler than Sandy Bridge and at lower TDPs (Intel will have variable TDP ratings for its CPUs starting with Ivy Bridge).
No. While there will be a "battery only" mode were both power and frequency is chopped down to run at a lower TDP many will still crank up to 35-40W TDP when plugged in. Apple isn't going to require you to change cases/fans/etc when it is plugged in versus on battery. So the "TDP while plugged in" will need to be the design constraint for the laptop.
That why it would be a dubious move by Apple to extremely dump thicknesss on the Mac Pro line. They would basically have to move to less powerful processors ( just as the MBA do).
Plus there is more surface area to dissipate heat.
For the 15". Not really. Again if you put the guts of a MBA 13" into a 15" case then somewhat. However, you have gutted the performance. And 15" of glass isn't exactly light. Not sure dramatically really saving any weight.
It is volume, not surface area, that is going to help get better heat dissipation properties. Pumping the heat into the Aluminum case so it gets scalding hot is a "fail". The case shouldn't be a the primary heat sink.
There is also plenty of room to accommodate a larger logic board with FireWire and perhaps even user-upgradeable RAM.
if too thin then the RAM slots go. Soldering RAM to the motherboard actually scrafices surface area rather than saves it. Cranked toooo thin and the SO-DIMM slots are too tall. Again yet another good reason not going Anorexia on a MBP design update.
Also, by 2012 there ought to be more Thunderbolt adapters available since Windows Ultrabooks will begin including the port.
That seems doubtful for much of 2012 since most of the vendors are grumbling about hitting the sub $999 price point with the current set of ports. Adding TB is only going to drive costs up. Sure they can swap the discrete USB 3.0 that most are currently including for a limited TB one, but
that feature will likely show up on larger laptops first.
There likely would even be room for a 1.8" hard drive as secondary storage.
If just swap HDD for the ODD there is plenty of room in the current design. The 1.8" capacities are not substantively larger than SSD storage sizes. They tend to cap out at 320GB whereas there is optional, yet expensive, 256GB drive for current MBA. In contrast, the 500GB standard drive in current MBPs is close to double in size. Few folks are going to want to slide backwards in storage capacity if the MBP is there primary computer.
If can push the HDD price down close to what the ODD price was and swap it for the ODD then would make more sense to run a hybrid system were use a 60-100 GB SSD (DIMM format perhaps ) as 'cache' and the HDD as the larger persistent store. Once the cache is large enough could spin the HDD much of time.
Or even just operate the small SSD and HDD independently. Put the "recue partition' on the HDD and the user just has to manage to put all of the "bulk" data onto the HDD.
Also, there's nothing to stop Apple from making the 15" version a bit thicker than the 11" and 13" versions.
At which point essentially have the current MBP 15" case. The current MBP isn't exactly bloated.
My guess is that the 17" will retain the existing form factor, much the same way that it is the only one left with ExpressCard.
ExpressCard is about as dead as DVD drives. Thunderbolt (TB) obviates that interface. Once there is a relatively cheap TB-ExpressCard dongle, it is likely toast even on the 17" model.
Two TB ports on a 17" MBP would be more widely useful than keeping that Card slot once the TB peripherals reach mainstream.