Here is my comment on their desktop computer: it has two pieces, one with most of the electronics plus a monitor, the other with an AC-to-DC converter plus a sub-woofer. I much prefer the more conventional division of duties in which one piece is a monitor, the other piece has a power supply and most of the electronics and the interface between the 2 pieces is some standard protocol like DVI-D, HDMI or DisplayPort.
I notice that their desktop computer uses a mobile CPU, which has advantages and disadvantages. One of the biggest advantages is portability, which is useful even in a "desktop" computer like the Mac mini. Specifically, the reduction in the demands on the cooling system allows the electronics and the case containing the electronics to be small and light. (A 2011 Mac mini or the recently-announced Chromebox for example weighs only 2.7 pounds including the AC adapter which in both cases is built-in.) But if you integrate the mobile CPU with a monitor, you lose the ability to unplug the box with the CPU from your monitor, carry it around and plug it into some other monitor or TV (which is something I do a lot with my Mac mini).
Worthy of note is the fact that the original Intel iMacs and Mac Minis shipped with Mobile processors (Intel Core/Core 2 TXXX rather than EXXX), for the reasons you mention.
Although some iMacs and maybe all iMacs now use desktop-class processors, all Mac minis still have mobile processors. (35 W TDP for the processors in the $599 and the $799 2011 models; 45 W TDP for the CPU in the 2011 Mac mini server.) Otherwise they couldn't be so small and light without overheating!
There are tradeoffs when you create abstraction layers. For instance, Apple's new ad talked about larger batteries they fitted by not making batteries easily replaceable - there were additional housing and adapters - which all took up room. This has been a general trend over many years.
I notice that their desktop computer uses a mobile CPU, which has advantages and disadvantages. One of the biggest advantages is portability, which is useful even in a "desktop" computer like the Mac mini. Specifically, the reduction in the demands on the cooling system allows the electronics and the case containing the electronics to be small and light. (A 2011 Mac mini or the recently-announced Chromebox for example weighs only 2.7 pounds including the AC adapter which in both cases is built-in.) But if you integrate the mobile CPU with a monitor, you lose the ability to unplug the box with the CPU from your monitor, carry it around and plug it into some other monitor or TV (which is something I do a lot with my Mac mini).