Hero pub winrates really don't mean that much (to an extent). Pretty sure morphling had 40-43% win when he was crazy OP during TI3.
Heroes with a high skill ceiling and low skill floor are at the bottom of winrates (wisp, QoP, furion admittedly, Invoker, etc...). Heroes with high skill floors sit at the top (wraith king, spectre, omni, etc)... Most heroes have a high skill ceiling in dota, but it's how well they do with minimal input, at the lowest levels of play (i.e. their skill floor), that usually determines their pub winrate. That's all it really shows.
How is qop, np, wisp, and invoker low skill floor and wk, spectre, omni high skill floor? Don't you mean the opposite? Its much easier to pick up wk compared to invoker.