My Taipan 4.9 is 15 years old, been bashed and crashed and treated like death by two teenagers for several years and is still strong and going.... 105 kg, fully 100lb lighter to push around the beach than the 17. I sail solo a lot and its weight was a BIG factor in selection.
Materials and bulid quality are what create strong boats and it is to be remembered the lighter the boat the less damage it can do itself when mistakes are made.
There is no reason to stay with heavy boats other than bad decisions early on in the structure of F18.
F18s are fully ten years behind the times re weight and next year that will be 11 and the year after that 12...you get what I am saying.
light is right.