Beside all these technical debates about the battery life, iGPU vs dGPU, IGZO or not, we don't know Apples business plan for this years Macbook lineup. And most of these hardware decisions depend on how they will set the price points for this lineup.
If they really choose to kill the cMBP, I expect some surprises. Maybe they keep last years 13" cMBP around for education, but they did not update the 15 cMBP in february. Furthermore the 512mb VRAM in the base model and the to high upgrade prices etc. are hints, that Apple tries to push people to the retina models.
The discontinuation would open a 500$ price gap between the 13'' rMBP with 2.6ghz (1,699$) and the 15'' rMBP entry model (2,199$). I can only speculate what they will do, but something unexpected like a 13'' quad or a lower spec 15'' rMBP don't seem so unlikely anymore.