Mere speculation: Isn't this just a result of the mixing of "Helpfulness" feature and the black-hat marketing / reviews purchasing?
As in now those selling "Reviews" for your app; something like $100 for around fifty 3 to 5 star reviews can justify their price by stating their reviewers have consistently ranked as being "Helpful" and always on the "front page" of any app review? And what we're seeing is the reviewers working for these black-hat intermediaries trying to up their overall review "weight"; whereby I'm assuming google takes into account your previous reviews (and their helpfulness) with how long your review now stays on the front page (much like comments staying on top of a HN thread).
Or it could just be a typical fad akin to wanting the personalized car registration of "A1", being top/first etc.
As in now those selling "Reviews" for your app; something like $100 for around fifty 3 to 5 star reviews can justify their price by stating their reviewers have consistently ranked as being "Helpful" and always on the "front page" of any app review? And what we're seeing is the reviewers working for these black-hat intermediaries trying to up their overall review "weight"; whereby I'm assuming google takes into account your previous reviews (and their helpfulness) with how long your review now stays on the front page (much like comments staying on top of a HN thread).
Or it could just be a typical fad akin to wanting the personalized car registration of "A1", being top/first etc.