I really do care about weight and dimensions. Before I used to buy the typical 3.5Kg laptops. When you carry an Acer around, you can feel the weight in your backpack, even when you walk around the office to go to a meeting. I switched to a MBA and I feel it like if it was a paper notebook. It is a huge difference. A perfect laptop for me would have the weight an dimensions of a MBA with almost the power of a MBP.
As for battery life, I need enough battery to be able to go to meetings without having to take the charger with me. It's not usual for me to work 8 hours without having a charger near to me. Also, as far as I know, the new Macs with USB-C, can be charged from an external battery pack.