On the other hand, if you make it so that the reward is way better than the alternative, you'll bog down the game alot since everyone and their mothers will be wasting 5 or so minutes every freaking round trying to figure how to improvise and play creatively, just so that they could exploit the rules.
Also, the easy/moderate/hard DCs shouldn't imply whether the damage values follow the same line low/ moderate/ high (respectively).
Sometimes an easy/small (easy DC) thing could activate a big/heavy (high damage) reaction.
As a DM it's your job to adjucate whether and how effectively such things work, always keeping in mind that the more creative the action, the more it should reward the player.
Also, the easy/moderate/hard DCs shouldn't imply whether the damage values follow the same line low/ moderate/ high (respectively).
Sometimes an easy/small (easy DC) thing could activate a big/heavy (high damage) reaction.
As a DM it's your job to adjucate whether and how effectively such things work, always keeping in mind that the more creative the action, the more it should reward the player.