In Lord of the Flies, Piggy is clearly clever boy, but he is a victim too. How is he important in the novel?

Piggy is the voice of intellect in the novel.  He and his glasses both represent the thinking side of mankind.  In Golding's view that mankind is defective, each person having a beast inside of him that emerges when rules are removed, reason and intellect are doomed because cruelty defies reason.  Golding felt that when mankind's cruel nature was unleashed, intelligence is crushed, just like Piggy was crushed by the rock that the completely savage Roger dropped on him.  Even at the end of the story, in chapter 11, Piggy still clings to the rules and intellect when he yells at the boys asking them what is better, to be savages or to follow the rules and be civilized.  We are shown Piggy's role as the voice of intellect early in the story when he is the one to suggest using the conch shell to summon the others.  Throughout the novel, Piggy is the one to make suggestions, to get Ralph, especially, to think and consider situations and actions.