I see Mac updates falling into three categories:
The main improvements of Haswell over Ivy Bridge are improved integrated graphics and reduced power consumption / heat dissipation.
Would you call the following a "big" update?
I think we'll just have to wait and see.
No, I do not see the microarchitecture cycles as more innovative than the process shrink cycles. I used to work at Intel writing circuit simulation software for the CPU designers, so I may have a biased perspective. The process shrink cycles are where we get to put more transistors into each CPU and that allows for more cores, bigger cache sizes, more execution units, etc. In my biased view, that's more important than the microarchitecture revisions.
Not necessarily. Three years and five years seem to be just about as common as four years.
No, minor upgrades occur as required. There is no roadmap.
If they don't happen with the Haswell release, then I guess the likelihood for Broadwell would be:
The main reason why Apple stopped producing 17" MBPs was the cost (more than a year ago) of 17" Retina displays (due to poor yields). The yields have improved and costs have dropped. Whether or not costs have dropped enough to introduce a 17" rMBP is unclear. Apple will be aware that the lack of availability over the last year will have resulted in some pent-up demand in addition to the usual ongoing demand. If I were Apple, I would be thinking about introducing a 17" rMBP in February 2014, with features not found in the 15" model, such as a 32GB option and two PCIe SSD slots.
I would be very surprised if there will be two form factors for the Haswell 15" rMBP. It seems to me that some people are way too caught up in the discrete versus integrated GPU question. I think, for example, the question of whether a 16GB BTO option for the 13" rMBP will be introduced with Haswell or Broadwell will be important for far more users.
