I'm not sure why the updated standard pros did not get a graphics or display resolution bump.
They did get a graphics bump.
Now MBP 15" GT 650M ( a 2012 GPU)
Before MBP 15" AMD 6750M / 6770M ( a 2011 GPU )
Those GPUs do
not have equivalent performance.
------------ pixel (GP/s) : texture (GT/s) : bandwidth (GB/s)
6770M ____ 5.8 : 17.4 : 57.6
GT 650M __ 13 : 26 : 64
There is no MBP 15" without a discrete GPU now. The 'gimped' aspect to the slower speeds CPU model is that it is a bit lite on memory; only 512MB. The top end has the same GPU and VRAM as what is driving the "Retina" model.
Nevermind, that the major difference between Sandy Bridge and Ivy Bridge is the improvements that came with the HD 4000. For one the HD 4000 can do OpenCL. The HD 3000 can't. So even the MBP 13" got a bump here.
As for screen resolutions.... the MBP 15 hiDPI difference is a major difference. Even within the same form factor it appears you can get the "hi res" (not really relative to the hiDPI model) models on the lower level MBP 15" with the slower CPU now. As matte+'hires' on the slower CPU. If I recall correctly that is a CTO option for that level. So again a change.
The MBP 13" screen is the same likely because it is easier and more straightforward to double it than the MBA 13" screen. As I said it isn't a forgone conclusion that the MBA 13" is going to be continued here. It could be on the chopping block and Apple needs something doubled from the MBP 13" to continue forward as the alternative for much higher resolution.
The 'hi res' displays of the MBA 11" and 13" are joke. Primarily because Mac OS X doesn't have resolution independent graphics. All they do is make the text and objects on the screen smaller. Smaller is not necessarily better or good resolution. Better resolution is what the "retina" mode does. The 'hi res' 13" screen really doesn't have enough more to really make a substantive difference. It is somewhat better, but not significantly better.
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I would still argue that people much more often connect external backup drives than they use the ODD.
But it isn't really a differentiating aspect between MBP 13" and MBA 13" anymore. More than likely the mainstream external drive is connected by USB 3.0 than by Ethernet (e.g., Time capsule) or FW 800 ( again a dongle or docking station evens the playing field. )
Yes there were more differences before but at the juncture going forward of which one to toss .... it is where they are now that matters. If judged at where were before it is a done deal... Apple sold far, far, far more MBP 13" than MBA 13". It is only now that the price is even that there is perhaps some glimmer that the MBA 13" could even attempt to even the ratio.