I've overhead conversations in Apple Stores in recent months, where employees were often having to explain the differences between the different MacBook lines, and trying to determine which was best for a user's needs. The MacBook Air really has been the outcast of the family since the MacBook's introduction last year. No Retina display, weaker processors, USB-A only… there was little to recommend it over a MacBook or 13" MacBook Pro.
It seems sensible to me that they would merge the MacBook and MacBook Air product lines. The two have so much overlap in form factor, price and performance, that it seems odd to keep all three portable lines when there are only slight differences between them. Apple seems to like keeping the shopping process simpler and more clearly-delineated, so it becomes obvious to the user if their use case warrants a "Pro" machine over the standard offering.
If they update the MacBook Air to include USB-C and a Retina display (and presumably drop the 11" model, which I cannot imagine has sold very well over the years), what are the points of differentiation between it and the MacBook? Processor? Slightly larger display? I can easily see Apple streamlining the lineup back to a two-model line, with two or three tiers in each one.
12" MacBook
13" MacBook
13" MacBook Pro
15" MacBook Pro
(With the Pro line offering faster processors, more storage, bigger batteries, more USB-C ports)
I'm a professional designer, but I'm not doing much processor-intensive work like 3D animation, video, or motion-graphic work. For 2D design and CAD, a 13" MacBook would probably be the sweet spot for me, offering a nice balance between acceptable performance and being thin and light for working away from the office and making presentations, with a display I could live with more easily for everyday work than the 12" display of the regular MacBook.
I'll take one in black, please!