Thanks for sharing your opinion. I agree with most of the your points. about others, I don't really know how it works.
Following the discussion in the comments, one thing that is clear is that SO must reinvent itself. The concept at the beginning was good, but the times have changed and some ideas are a bit old style, I guess.
I don't like either the downvoting system, it's just negative, it should be managed internally by moderators just in case the post is completely wrong, and warn the user who wrote it about the problem of the question/answer.
Also, the duplication is negative, as you or others have said, it'd be better to add a link or relationship with another question, and that's all.
I also feel a bit frustrated when I'm going to answer something, I'm just sure someone's going to do it faster than me because I'm the kind of person that thinks several times while writing, and tries to correct the post properly before clicking on the submit button :-). Anyway, in the end, personally I don't mind too much, I sometimes let my answer there, or just discard and move on.
Of course a good advice to newcomers is to read all the answers to a question, and may be similar questions. Never do copy & paste, but try to understand what the code is doing.
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