The other thread, "What has time and technology done for you?" has gotten bogged down in a discussion of stiffness.
I'm still interested in the original question, so I came up with a list of the categories in which there have been some technological changes in the last 50 years. Which do you think have had the most impact on small cats, for better or worse, and why?

• Rope
  Blocks
  Masts (designs and materials)
  Sails (designs and materials)
  Spinnakers (Not spinnakers, per se, but the design of the asymmetrical spinnaker, which made it possible for spinnakers to be used effectively on multihulls).
  Daggerboards
  Rudders
  Traveler systems
  Crossbeams
  Hull shape
  Hull construction
  Trampolines
  Life jacket designs
  Trapeze harness designs
  Drysuit designs and materials
  Hydrofoils (not relevant because still in development stage)

Please add anything I may have forgotten.