I don't think it's necessary. With quoting, it's pretty easy to follow conversations and the evolution of a thread.
Either put the original post or a wiki on the top of each page of a thread. For a multipage thread, a newcomer will likely not read every post. If the OP does not keep up the original post to reflect the evolution of a thread, a wiki would help with updates.
But to contradict myself , if we did a wiki, how would we ever add editing the wiki to status points?
I'm sure the dev team already has that planned out. However, it appears to be on a need-to-know basis, and you and I don't need to know. Seriously, Randy has indicated that the points calculations will be dynamic, and based on contributions to the site, so thinks like wiki maintenance will surely figure into it in the future.
Kinda sorta a little bit joking about tracking points, especially since If we get a sticky wiki, it will be a better m. for all!
It probably needs to be case-by-case. Some threads this would suit and some it wouldn't or wouldn't matter for. Someone else mentioned making it possible for the OP or a subsequent poster to create a wikipost as the second post of the thread. That might allow it to happen when it is relevant without forcing that structure into every thread.
In practice, too (see wikipedia for example). The value of such edits is somewhat more difficult to assess, but then we do have posts of rather different value, too (see counting down from 123,456 for my favourite example).
I've noticed this seems to be the case in the Launch Meetup threads; at least they're behaving that way on my computer, could someone confirm it's working thus for them? If so, then the capability is already there in the system, and it can be used on a case-by-case basis. Perhaps there can be a checkbox for the OP to set this function?
I am thinking (from another poster in another thread) that it would be OP selected. By reducing the number of threads that have the feature, there would be less need for it to be disabled on a global scale.