True! But I think that if the prize will be for example 100 or 200 SP delegated then it worth much more than a 35 sdb as reward. In this way whales will gain as they always will be the owners of this SP delegated but we will win too because the reward is higher.
You can increase the number of winners or you can increase the number of challenges. My point is that in this way everyone should be happy. Better a hen that will give eggs tomorrow than eat an egg today!