I would welcome the SuperDrive lose, but it would be a bummer for the 13" MPB to lose the 2.5" HDD/SSD bay. I need upgradability and the 15" is overkill for me, since I use an external monitor while in my office or at home. I want something light that I can carry to meetings and when traveling.I second this except for one thing. I think that instead of having a 13 Pro and a 13 air they will combine them to become the new 13inch macbook air. Then the line up would be the macbook air 11.6 and the 13.3 then the Macbook Pro line with the 15 and 17 inch.
Upgradeability is critical for me.