The main point of the changes seems to be encourage people to get to stadium early and a 15% discount is actually pretty bloody generous imo. The 10% then comes into effect until half hour before kick off, and then as it is time to take your seat it goes down to 5% which is still better than...
I'm still going to buy stuff if I want it and not if I don't. I consider the cashback an added bonus, not an essential part of my day. You only really 'lose' out half an hour each side of kick off and the final whistle which i am not too bothered about. Ironically my saturday pie and pint combo...