+1 I was just coming here to make the same suggestion.
This would be IDEAL for those long threads where there are dozens of pages of posts. All of the most essential information can be kept up to date in the wiki post, with links to the relevant posts within the thread.
It would also make it easier for collaboration on the many threads where a single person (the original poster) keeps the first post updated.
Definitely a worthwhile plug-in to consider!