I could have purchased any MBP or MacPro or whatever, and chose the 13". The specs of the 13" are already more than I need for what I do(that said, I'm getting a SSD because I WANT one, and 8GB of RAM just because I'm already going to have it open and for ~$100 why not.)
I wanted the smaller dimensions and footprint of the 13", at the time it was the last gen Air, and I would still choose the 13" MBP over the current Air. The 13" fits perfectly in my messenger bag, I honestly don't think the 15" would fit and if it did I would have to stretch it to fit it in. The only thing I wish the 13" had was the option for a high res screen, something like the Air's resolution with the quality of the Pro's would be the only upgrade I want. Hopefully the redesign has at least a 1440x900, and the option of anti glare would be nice.
I wanted the smaller dimensions and footprint of the 13", at the time it was the last gen Air, and I would still choose the 13" MBP over the current Air. The 13" fits perfectly in my messenger bag, I honestly don't think the 15" would fit and if it did I would have to stretch it to fit it in. The only thing I wish the 13" had was the option for a high res screen, something like the Air's resolution with the quality of the Pro's would be the only upgrade I want. Hopefully the redesign has at least a 1440x900, and the option of anti glare would be nice.