Honestly I don't understand how this is something that can be said to have "swung too far in the opposite direction". That implies there's a level of minority representation in media which is "just right" and that exceeding it is a problem. What is that level, and why is it where you've placed it? Why exactly is it a problem if you see more minority representation than you personally think is justified? Can minority actors and characters not carry a story as well as straight white men?
Seeing more and more minority characters in our films and TV just isn't a problem. It's evidence of our society changing for the better. If you can point to an example of how the quality of the media genuinely suffers (as opposed to just jarring with your nostalgic childhood memories) then that'd be an interesting discussion. However I'm pretty sure it's not worse - it's just different.