In 2015 BMW will reveal totally new bmw x6 and here are a few reasons to wait and get the new one:
1. Design. New BMW X6 will have a more agressive look. Something combined from X4 and X5 (F15).
2. Space. New BMW X6 will be larger and wider plus there will be more space inside.
3. Comfort. Many people complained about ride quality on current x6(e71). New X6 will have a different chassis, as I suppose based on F series thus ride will be more comfortable. Also there will be adaptive suspension as an option.
4. Performance. Bmw managed to obtain weight reduction by using some different material in car construction.
Finally I would say you will feel bad when just one year after you bought current BMW X6 (E71) new model will come out and I am sure you will like it.
For now I think getting an F10 530d xDrive is a great deal, it just got LCI and you can drive it for 1-2 years and then switch to new X6.