Why? why would apple start reducing prices on their hardware especially if its a new release/design if anything there will be more to pay, expectations like this are similar to those who expect any new macs to be shipped out with a GTX 980.
If Apple increased the price of the retina's over normal MBP's was because of the SSD and the display. Now retina displays don't cost the same as 3 years ago and SSD's are much cheaper too.
If it costs more, it'll enter the price range of 13"'s rMBP. Not asking for a price reduction, but mantaining the price of the 13" Air would be the good way to go. Also, Apple reduced prices before in Airs with same hardware, and doubled the amount of ram of 15"'s mantaining the same price, so I don't see why Apple would increase a price now.