This is probably a lot of complexity to implement, but I think it's something that would be helpful to consider. Something that can be thought of down the road.
There are many who regard the ability to identify and close duplicates to be one of the more valuable assets that the Stack Exchange engine offers. Personally, I've found "close-as-duplicate" to be one of the nicer close reasons because unlike the others it still attempts to answer the question.
Nevertheless, a blog post was written that, among other things, considered that the linking made us tantamount to the evils which one has to deal with on other sites. While I mostly concur with the thought, I have concerns primarily about the issue of fragmentation of content. Attracting the same answers isn't as much of a problem, in my eyes, as the potential for useful information to all variants being isolated in only one variant. This means that if people search under the wrong terms, they could find the "solution" to their problem but are bereft of the useful information present in the other posting.
The current merging system helps solve both problems. It mixes all the answers into one place, so people won't miss on information. And it groups all of the "same" answers together in one question, which allows people to see them all on the same page. I think, however, we can take this one step further.
When a question is merged (and only on merge), answers to the "parent" question could be reflected across all of the "child" counterparts. That way, instead of having to deal with a link, they still get their answer immediately. We avoid duplication of content, we avoid fragmentation, but we still allow people a variety of terminology in order to locate the same answers. In an ideal scenario, these are actual references to the posts on the parent question and not separate posts that require some complexly chained update script. Instead, when I vote up a good answer, I'm actually voting up the answer on the original question. Where it gets tricky is in acceptance, and also what about the ability to post answers... which is why I know this probably won't happen any time soon.
I suggest this is only done for merging because as mentioned on the blog, there isn't always just a singular canonical question. Sometimes we do run into marginal duplicates, or cases of a specific variant being closed as a dupe of a general question. Merging is traditionally done after it is absolutely considered that the two questions are identical (at least, on Gaming it is like that). These are the cases where having it all in one question does work.---
I know we already have automatic redirects in a small fashion. But as explained in the answer there, it doesn't really do anything for the closed question that isn't deleted.