White is the colour that goes with Apple products. Mac computers and equipments are in white. Some argued as a plus point while other didn't like it. For me colour is not a problem. However, it seems like Apple is having problems releasing white iPhone 4 even though they advertise it in the iPhone 4 gallery.
Apple even removed the white iPhone 4 from the Apple store but still you can see it in the iphone gallery. There were rumors that Apple is going to launch long waited white iPhone 4, but it seems like it is not going to happened soon.
Some of the reasons that might cause the delay
sensor issues
light leaks
problems bonding the color to the glass
inability to match the home button to the faceplate
Is there a link between the reason news; Chinese iPhone factory workers getting sick? May be or may be not. However, there is a possibility that this is a part of Apples marketing strategy. Once the iPhone 4 (black) sells are reduced they will introduce the white iPhone 4 with upgrades.
Are you are waiting to buy white iPhone 4?