There's no compelling reason not to make the post Community Wiki
First off, turning a post into a community wiki makes the post belong to the community, which is something that has been done with a decent number of masterposts. As this post is also a masterpost now (look at its timeline, it has had countless questions closed and merged into it, it would make sense that this question follows suit. Grace Note's post on the SO blog is not set-in-stone policy, but only a guideline that individual sites (or even moderators/users) can choose to follow/ignore as they see fit.
Secondly, it keeps trivial edits (such as adding cards or example images) out of the review queue. Low-quality edits aren't that big of an issue -- rollbacks exist, and the masterposts that are already community wiki aren't vandalized often. While, yes, the edit queue is fast, it still isn't a good idea to clog it with edits that don't need reviews. This comes even more into effect when you realize that editors are supposed to verify that information edited into posts is factually correct (although everyone seems to ignore that rule for the sake of brevity). With a CW, there's an implied trust that users know what they're talking about (which is, in fact, the concept of reputation).
Being a community wiki doesn't encourage bad edits or answers any more than a regular question. In fact, to that regard, I've already protected this question as there has been at least one case of a "me too!" post, and I can only see that number growing as time goes on.
We're already breaking plenty of rules with this post (for example, it should be closed as a bug, we're allowing edits of new cards/examples, and so on), so it's obviously a special snowflake. According to our own edit rules, further examples and cards should be blocked as an "attempt to reply," but this behavior is tolerated here precisely because this is meant to be a canonical masterpost.
Finally, there's the question of symbolism. This question has been asked by many people, each adding their own little spin on to the original question. Putting this question into the ownership and control of the community can only benefit it and make the question better and easier to find.