The Public Test Realm is usually to give players a chance to help test and find bugs to new content. There has not been any new real Competitive Mode testing since season 4 when they revamped the tie-breaker system for Assault Maps. Really if they make policy changes, they will do so when they are ready to commit to them. Revealing anything without being ready to commit to it is a bad idea.
About Role Queue, I won’t object to it, but it will not fix many problems and it may actually create even worse problems. Yeah you may get a balanced team comp right out of the gate, but Overwatch is about switching heroes and whole team compositions. If someone fails to perform their role in any given, they would be subjected to worse abusive from toxic players.
Also, don’t forget the older forums have had many developer responses to many questions about Competitive that so many players have forgotten, I maintain an F.A.Q. thread in the Competitive Discussion forum so that players have a single destination to most Blizzard Responses.