People complained about not having anything to do with their karma, and therefore karma gain from events was nerfed.
Instead of nerfing karma, why not incorporate more incentives for players to spend karma on, and buffing karma gain from events? There are an almost limitless amount of aesthetic and performance options that can be incorporated into the karma system such as armor re-tuning, dye purchasing, and so forth. Increasing karma for non-champion events will also give players more incentive to do events other than farm champions… which (lets face it) practically everyone is doing now and damaging the diversity of game play.