Sorry, I missed that this was an extract recipe. I think El Pistolero is correct; I don't think your gravity is to blame. If you were looking for a hoppier flavor - typical IPA - then I would up the hops, particularly the Cascades. And I think you were headed in the right direction by dry-hopping.
When I was doing extract based recipes, it seemed to me that I could
never get the hop profile I really desired. Then, I began to up the amount of hops suggested and that seemed to do the trick! Again, just my opinion on it.
And, yes, sparging helps, IMO. It took me about two years of brewing extract recipes before I read it somewhere and decided to try it! There's some good reading about it
here,
here and
here!
It looks like you did everything right. If the yeast was a packet of dry yeast that came with the kit, then I would suggest using a liquid yeast next time, either White Labs or Wyeast.