I see more and more exact duplicates on SO. Instead of being merged they are being simply closed. I think this is very big disservice to SO. Why don't moderators merge duplicates? Why don't owners of the site do anything about this?
It's disservice because this way we have more and more junk. Duplicates are duplicates and should be merged so that information in in one place.
If the duplicate has no answers then there is no benefit to merging.
Of course there is. You don't need to waste your time with dupes.
It also means that the search routes to the main question are diminished which makes the posting of new duplicates more likely
There's easy solution for this which I gave in Users search for questions not answers - what does it tell us? back in march.
If both questions have answers that have been accepted, which one should be unaccpeted?
There are plenty of solutions. You accept most voted accepted answer or the first accepted answer or both (I think this is be the best). Yes, there will be possibility of many accepted answers to one question. So what?
When a question is closed as a duplicate, there is a link to the duplicate question. What more do you want?
I don't want yet another link. I want to have all answers to some problem in one place. Is this that hard? Isn't this natural expectation?
Removal of the question means that the text in it is no longer searchable - that's a disservice.
See my answer above to Scrooge's comment.