If you guys are measuring the unevenness of the LED backlight, you're going to be disappointed that there is no fix. The side mounted LEDs will always have uneven backlighting because of the manufacturing process of side-mounted LEDs. There are 2 ways to manufacture better screens. 1st is HD Super AMOLED Plus and the 2nd is to manufacture IPS LCDs with LED backlighting mounted from the back. The only method to produce a screen as thin as the iPad screen now would be to go with the HD Super AMOLED Plus screen which would in turn raise costs quite a bit. The main question is: would you be willing to pay a $200-300 premium for the HD Super AMOLED Plus screen? If yes, then you should contact Apple's iPad feedback page here: http://www.apple.com/feedback/ipad.html
If you aren't willing to pay $200-300 premium for the screen on top of the current cost, then we don't need such a high quality screen. It's a cost balancing act and right now the 2012 iPad is doing better than it's competitors for the cost balance. If there aren't enough people that like the added cost for the HD Super AMOLED Plus screen, it means that you're in the minority for wanting a better display at higher cost.
If you aren't willing to pay $200-300 premium for the screen on top of the current cost, then we don't need such a high quality screen. It's a cost balancing act and right now the 2012 iPad is doing better than it's competitors for the cost balance. If there aren't enough people that like the added cost for the HD Super AMOLED Plus screen, it means that you're in the minority for wanting a better display at higher cost.