The web app behind PH is trivial. You still need a human to curate and build hype around the thing, and therein lies the problem. PH is rigged because Silicon Valley is rigged.
I would be interested in developing the app, but it's putting the cart before the horse.
But in those cases, looking at the poster's history and then reporting them to mods is a pretty good (albeit manual) solution.
I think Reddit-PH would still stand a better chance since it discourages anonymity and participation for non-established users.
Besides shadow banning, do you know what exactly Reddit does to make it difficult to game? I'd like to understand this better.