my proposal is a end year box with a code for every VIP player who bought KP between dec 2015~ dec 2016.
Something like that:
If you spend...
5k you get 1 box
10k get 3 boxes
20k- 8 boxes
30k -13 boxes
50k = 100% chance items
So.. if you bought 25k this year, you could spend more 5kp to get an amazing box with awesome items.
People get real incentive to buy It (like a x-max prize)