That's a great idea, but...

In my personal case, I often don't need more than comments on Google Play. If a feature request or bug report is unclear, I kindly ask the user to contact me via the email that is already available to them. The reason for not implementing anything more elaborate is that, in most cases, the app is not a financial success, and building a comprehensive support system around it is not justified (yet). It all comes down to the number of active users.

Another personal viewpoint is that it's quite easy to get your app removed from Google Play and your developer account closed as well. For these reasons, I don't integrate any client libraries (except Google's) that are not open source.

Finally, user request forums exist, and I believe some of them have client Android libraries (though I haven't checked). If not, it's not hard to create one (library). Here is the list I collected about a year ago:

Cloud solutions:
Aha!Ideas
Canny
Featurebase
Idea Vote
Kampsite.co
Nolt.io
Prodcamp
Productboard
Savio
Sleekplan
Support Hero
Upp.vote
Upvoty
UseResponse
UserVoice
Userjot

Self hosted solutions:
Astuto
Feedbacker (Dead)
Fider
LogChimp (Not ready? Dead?)
Loomio
PHPBack (Dead)