During the VIVOBAREFOOT Coaching Program course, Lee Saxby, the participants, and I decided on the definition the perfect minimalist shoe. This is what we came up with in my own words:
1) Allows for maximum proprioception for the intended purpose. The purpose defines the trade-offs necessary for thermal and puncture protection. 2) Allows for appropriate shifts in the body’s centre of gravity in terms of sole thickness and heel to toe differential. 3) Allows for complete natural movement of the foot in terms of room and flexibility for bone structure and elasticity as well as proper heat dissipation.
My shoe reviews from now on will include how well the shoe satisfies this criteria.
It's important to keep in mind that the purpose of the shoe is incredibly important in this definition. For example, the puncture protection necessary for a trail running shoe is going to be much greater than that necessary for a casual or work appropriate shoe. A winter shoe is going to reduce proprioception because of the extra insulation required for thermal protection.