To the extent that the burgeoning field of metascience has a policy agenda, it is that science should be governed by rigorous science. We should test scientific practices using the scientific method. In large part, this policy agenda has included encouraging the adoption of methods like the randomized control trial (RCT) as the gold standard for assessing a whole range of science policymaking issues, from addressing the reproducibility crisis in various fields to judging the effectiveness of various grantmaking structures.
There's an interesting sociology paper (Peterson and Panofsky, 2020) that looks at the "metascience movement" (rather than the field of metascience) as a social movement of moral entrepeneurs, crystallizing a sense of emergency (and resultant solutions). Also includes an interesting ethnography read-out of panel discussions from a metascience conference . Not sure if this was intentional, but one section in this paper is titled 'The fragile unity of metascience", similar to this post!
Have you read "Science-Mart" by Mirowski? It's an interesting study / historiography of funding policy in the US for the last 100 years, and of the idea of measuring output
I suspect that some of the social sciences are not included in your definition of science because in some cases RCTs are impossible, however my comment was about the need to embrace other skills - philosophical, political, aesthetic. In universities here (Australia) there has been a continuing trend over several decades to devalue learning in these areas in favour of technology and engineering. Turning this around is a difficult ask.