I like your proposal, but people are coming because they like the site and what's wrong with that?
My "dream" is to reach the position where say 85% - 95% of UK and Schengen questions are duplicates. This is not at all preposterous.
Essentially, we have reached this with almost all Schengen questions. There are odd one-offs, but there's been a dramatic decrease in Schengen questions overall. I am guessing that people search for it and see a great answer that satisfies them and they go away without asking a new question.
If we had a close reason called "failure to perform basic research" there would be a lot fewer silly questions IMHO.
UK visas are a bit more difficult, but there is enough in the question/answer store where duplicates can be marked whereas 18 months ago every question was "unique". When you boil it all down, there's only about 7 ways you can get a UK refusal. A funds parking thing, a credibility thing, and so on. Read through the question/answer store check me out on it!
What brought me to TSE originally was the chance to see wonderful questions about for example the Danube Valley, Big Sur and the like. Give the visa thing time to evolve.
I hope that someone who knows the SO API would write a time series plot on 'Schengen' and 'UK' frequencies over that past 12 months and we can put some hard data to your question. I bet they are decreasing. I would also bet that they have the poorest accept rate, but that's a different story.