The bump in CPU speed only being minor (i.e a higher end old model is slightly faster than a lower end new model) is more or less to be expected when you remember that Haswell primarily focuses on integrated GPU performance. Intel themselves talked about 6% in multi and single thread tasks and 8% in vector processing. You can see the focus on improving the integrated graphics from the 5200 being on par with the 650M from the previous two models and giving the 750 a run for it's money. In other words, Apple didn't switch to integrated graphics even for the baseline 15" model for no reason.
I personally may be able to afford a new 15" rMBP, even the model with the dedicated GPU, but being as cheap as I am (I've never paid full retail price for any Apple computer) I simply can't motivate spending that kind of money when I can get a second had late 2013 or mid 2012 machine for about half the price. The difference becomes even more nuanced when you factor what I'd get from selling my current machine.
Having a Bachelor's in Computer Engineering (working on my Master's at the moment) and having done quite a lot of programming, including CUDA work, I don't see any point in buying a (new) 15" Pro with dedicated graphics unless you want or need to work on CUDA stuff right on your own machine. Like I already mentioned in this topic, I agonized on the subject for some time before coming to the conclusion that upgrading from my early 2011 machine would have been a waste of money even thou it's the one with the crappy dedicated GPU.
