Eric Slivka:

The new MacBook Air is said to take on a slimmer design and arrive in 13-inch and 15-inch sizes, but it is unclear whether an 11-inch model will also be included. The slimmer design will be enabled by “fully redesigned” internal components across the board, and Apple is reportedly currently working with its suppliers to develop these new components.

I full expected the Retina 12″ MacBook to drop in price in the future, replacing the Airs completely, and the MacBook Pros to be redesigned with thinner and lighter cases. If Apple chooses to refresh the Air lineup with a 15″ model in addition to the 13″ one, I would assume they’d both get Retina screens. The differentiation would have to happen predominantly at CPU level. The current 15″ rMBPs are all i7 quads, which leaves room for dual-core i5 and i7 CPUs. I’m assuming that the rumoured 13″ Air would get the ULV¹ CPUs, which are placed between the Core M from the 12″ MacBook and i5/i7 dual-core in the current rMBP 13″, in terms of processing power.

While this wouldn’t simplify their MacBook line-up, it would separate the consumer models from the MacBook Pros. Also, perhaps an updated 13″ rMBP would get quad-core i5 and i7 CPUs, further distancing itself from the Air.