What incentive do publication editors have to boost writing from outside their own publications? Also, to give the power to a limited number of publications (top performing I'm assuming) would skew the algorithms in favour of these genres. Why not create well-assessed curators on an independent Medium team to ensure they're not biased.
Medium is an open platform that is supposed to allow writers from around the world a space to create, experiment and find readers. I fear this move may create a platform with similar gatekeeping issues as the traditional publishing industry.