I especially like this because it flattens series / preference. There's no "Series FF"-style shenanigans where founders can convert and cash out in later rounds

I especially like this because it flattens series / preference. There's no "Series FF"-style shenanigans where founders can convert and cash out in later rounds while their VCs hold out for a fanciful exit, leaving employees high and dry, and there's no opportunity for broken preferred/common conversion that lets VCs exit with a much better deal than their founders or employees get - everyone owns the same shares. Sadly, because it actually aligns VCs, founders, and employees in the same pool, I don't see this being accepted by very many investors.