wolram - Huygens did more than just take pictures. It also took many atmospheric measurements (physical, chemical, photochemical, magnetic) on its way down to the surface. The photos give broader (although less detailed) information regarding things like geology, "hydro"geology, etc. Huygens is also just one part of the overall Cassini mission.
errorist - - They can't just put the latest technology on spacecraft. There is several years testing & modifications required to make sure each component can survive liftoff, survive the journey (temperature, radiation, etc.), and survive the landing. Plus, like s3nn0c said, it was launched 7 years ago. So, 7 years plus a few more for testing/modifications is the technology level you're working with. Just think how far computers have come in the past 10 years.