Trying to stop astroturf reviewers is like shoveling against the tide. We as consumers have to understand that crowd-sourced online reviews are fundamentally of no value.
Bring back the professional reviewer with knowledge, a track record, and a reputation.
This is right, except that consumer reviews that go into detail or objectively mention specific pros/cons of the app can be useful. For example, if reviews on an app say "it makes you buy an in-app purchase to do (something)", they can be useful. The stars mean nothing.