The question is - has this policy reduced the number of spammy, irrelevant or ignorant comments on the Play store. It used to be several notches below the quality of Youtube comments.
It's a trade off, and real name policies don't only exclude negative posters.
(To expand: I tested someone's js project on reddit just yesterday, offering my platform, multiple browsers, a decent writeup, images/screenshots etc. But my reddit account is fully anonymous. If my real name was required, s/he never would have gotten that free help)