I use grasshoppers every summer. I think they are a great addition to the diet. If yours are wild caught, like the ones I use, then of course one has to be aware of possible parasite exposure. if the grasshoppers are large, with spiny hind jumping legs, its possible that they could scratch/hurt the chameleons mouth. If your chameleon is a good "chewer" and your not using them all the time, dont worry about it. if you are using a lot of large grasshoppers, consider removing the hind legs.
As for being a "staple" - I personally dont think having a staple of any kind is the way to go. Instead, variety is my thing. I try not to let any one prey item make up more than 20% of my chameleons diet, and generally use 6-12 different feeders per month.