Learfan is the perfect example of the wrong way to design a composite aircraft. Instead of building an aircraft to capitalize upon the strengths of high performance composites, the Learfan team chose to apply composites in the same way they would metal in conventional aircraft with the associated fasteners and metallic load carrying structure. There was an early attempt to filament wind the fuselage which met with some early success until conservative management decided upon tape layups in order to reduce risk. The Learfan and the Beechcraft Starship in many ways were either ill-conceived or poorly executed. Metal construction is fine.
Composite construction is also fine.
Each must be applied to a design according to its strengths and with a carefully thought out set of tradeoffs in mind. In other words, there are too many folks out there in the homebuilt movement who think one-dimensionally concerning building materials and applications. There is also too much religious belief in one design guru or another. Also remember that kit manufacturers and designers frequently have different motivations from those of the builders. Sales and liability may dictate that alternate construction methods and competing designs be trashed in the popular press.