tried to ride the WIR (tuflite) - very clunky and awkward. It didn't do anything well...but I'm a longboard newb
Agree. A cruiser should have some mass and glide. Taking a shape like that and then cutting out maybe 50% of the weight and making it out of a far more buoyant material is unnecesarily -imo- messing with a successful formula. These kind of boards have been made out of poly cores for 50 years and it just makes sense to me to use time-tested materials for a time-tested shape.