Google has updated its Play Store guidelines to again clamp down on how developers can list their apps. The keyword spam section of the support site now includes a rule that specifically forbids developers from inserting user testimonials into app descriptions. Doing so could get an app pulled.
The new rule is under the "Unrelated keywords or references" header and reads as follows.
Please do not include user testimonials in your app description. They tend to be dubious and are frequently utilized to include references to popular search terms and competitor apps in violation of the policies outlined here. Let your users speak for themselves via Play's comment review system.
If you've spent any time looking at the reviews posted in the Play Store, you'll see why Google is doing this. There's not much in the way of insightful commentary, and they don't provide any information the developer couldn't just add themselves. The main issue is that devs often choose to include reviews that make reference to popular apps or use important keywords. Google has long since outlawed keyword stuffing in the Play Store.
It's an understandable decision from Google's point of view—this makes search more reliable for users. Developers might be miffed if they were honestly trying to highlight interesting and positive reviews. Still, plenty of apps and games have testimonials and other text superimposed on screenshots. I suppose you could go that route and avoid Google's ire.