@John123: I bet your right, but you make it sound like Apple could simply increase the battery life by 65% with Haswell, like they did with the 2013 Air. I expect only a marginal increase. I have no idea how they could get the same results (2-5hours extra) with the 15 rMBP.
The retina screen is the biggest battery eater. They dont use ULV processors for 15 rMBP, the power consumption of Iris Pro/ Quad is not that low and the gained space from the dedicated card is not big. These point indicate for me, that an increase of one or two hours with light usage is possible. Maybe with less power hungry IGZO Displays, Mavericks, a special Intel solution and a clever battery design they could add more. But thats unlikely.
So the new model could get extra 1-2 hours of battery life , 3-4% increase of processor power and 25% decrease of graphics power. Even with Wifi AC and a faster SSD, I dont think thats a huge upgrade. And under heavy load i expect that it will kill battery life as fast as the previous generation. People, who need battery life could buy the 2013 Air with up to 12 hours. The 15 rMBP will always be behind due to its power hungry performance parts.