Macbook Pro becomes, "Macbook", or Apples keeps Pro and Air
This is what I think is going to happen to the Macbook Pro 2012.
1. The optical disk drive is going to be gone. There is no question about this one because of what is written in this article:
("They're all going to look like MacBook Airs," one person familiar with the new MacBook Pro designs told AppleInsider.)
2. At this time, technology is not available to make a Macbook Air be as equal or powerful as a Macbook Pro, because it is simply too thin. A Macbook Air would require an ultra low voltage cpu while a Macbook Pro would use a standard voltage cpu. With the optical disk drive removed, Apple would certainly be able to make the 2012 Macbook Pro be more thinner and lightweight, but not as thin as a Macbook Air.
This means 2 things will possibly happen:
A. A thinner, lighter Macbook Pro, with no ODD, dedicated graphics, and a standard voltage cpu, could eliminate the need for the Macbook Air. Therefore, there will be no more Macbook Air, only the Macbook Pro.
B. Apple refreshes the 2012 Macbook Air with an ultra low voltage cpu, Intel integrated graphics, and flash storage, along with the redesigned 2012 Macbook Pro (no ODD, dedicated graphics, standard voltage cpu, Retina Display.
Therefore, there will be no merging between the Macbook Air and the Macbook Pro. Either Apple makes a thinner, lighter Macbook Pro, and removes the Macbook Air. Or Apple makes a thinner, lighter Macbook Pro, and keeps the Macbook Air.