What to do when a 'duplicate' question and answer are better than the 'duplicated' ones?

Question

Today I flagged Avoid height flickering in a block when hiding content with \only as a possible duplicate of Avoiding jumping frames in beamer.

Some other users also marked it as a duplicate, but Charles Stewart wrote a comment explaining that he considers these duplicate question and answer better than the original ones. I agree with him but I didn't consider this aspect when flagged.

So, what it's supposed should I do to. Should all original questions be flagged as duplicates of new ones? Should do nothing? Should I edit original ones including a link to duplicates?

In Closing questions as duplicates when the duplicate's accepted answer isn't ideal there's a similar discussion but now also the question is better.

Answer 1

There isn't really a good process for this. Some options:

1. Merge the duplicated questions, which ensures the best answer can remain. I gather than this is time-consuming for moderators;
2. Users with >3k rep. can reopen the closed questions and then close the others as duplicates of it. This is a haphazard plan, since the close voting has to happen after the post is reopened, and it is hard to keep enough users performing these actions in the 2-day period before close/reopen votes expire;
3. Have a moderator do the steps in stage 2; or
4. Write a model question that all the other questions can be duplicates of and close the three posts as duplicates of this. Then we don't have the best answer in the right place.

Option 3 is the least bad, and can be started by the flagging you suggest,, but I don't like putting this tiresome task on the moderators. I consider it a flaw of the duplicate-closing system that newer posts nearly always get closed as duplicate of older posts, even though that very frequently results in the weaker question being the one that is left open to attract more attention. If the review system allowed an option to vote for the reverse close, I think that would help a lot.

Postscript

Jeff Atwood seems to recommend merging for this case; see Improved Question Merging

Answer 2

How about the following procedure (if applicable):

From the new question, remove everything which has been asked already and put a link to the old question instead. Then keep just the new parts of the question.

If this is done quite early after the question was posed, the answers probably will also be more focussed on the new aspects.