I think it will be significantly smaller. The original xbox was nearly a PC, I expect the new one to have a much simpler design now that microsoft is dropping the PC baggage. I expect a design somewhat similar to the gamecube, though not as small, and the memory controller, sound chip, and graphics probably won't be all on one chip.
I expect the xbox2 to produce at least 50% more heat than the original. Depending on clock speed, the cpu may or may not produce more heat than the xcpu, but I don't see how it can be equipped with a top of the line gpu and not generate significantly more heat than the xgpu.
I would not be surprised to see the xbox2 have a weaker gpu for the time period than the xbox1 did, but a faster cpu for the time period.
Online will play a bigger role, and cost more.
I expect the xbox2 to produce at least 50% more heat than the original. Depending on clock speed, the cpu may or may not produce more heat than the xcpu, but I don't see how it can be equipped with a top of the line gpu and not generate significantly more heat than the xgpu.
I would not be surprised to see the xbox2 have a weaker gpu for the time period than the xbox1 did, but a faster cpu for the time period.
Online will play a bigger role, and cost more.