If I could choose the material for my shoe upper, it would be wool/felt for any parts that don't require high strength. Wool has so many great properties. It both insulates and ventilates. It dries fast. It's lightweight. it's biodegradable. It occurs naturally in colors that are appropriate for business footwear (alpaca particularly has a wide range of hues). The only aspect where it lacks is in strength, however, as we see with huaraches, only a minimal amount of reinforcement is actually necessary for keeping a sole underfoot. I would like shoes that employ wool/felt for much of the shoe upper. Like if Stem or Softstar swapped their current upper materials with wool felt.