I hate to play devils advocate but I think stopping duplicate questions has made it easier to find answers and it forces all opinions on into one place.

I actually think it helps many developers and new people. A programming skill is learning how read other peoples code or apply their ideas to your code base.

The biggest problem I’ve experienced is one of trust that has come about from the websites age. Now we’ve had 10 years of Stack overflow, when you visit a question you can’t necessarily be sure if the accepted answer is the modern or best solution or not.