There are of course legitimate uses for unlimited editing. Unfortunately as the site gets bigger, you start to see a lot of people abusing it.
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Or you could still have rage quitters go and just edit every post they made to be, "..."
It is the latter which I've seen on my sites, someone going back through all their old posts and removing the content, thus rendering large portions of the thread nonsensical.
For this reason I also have a limited editing time for posts on my sites.
If someone needs a post edited after that time, we just encourage them to report the post and request an edit be made by the moderators on their behalf. Doesn't happen often enough to cause much extra work.
I just don't see an upside to hiding edits from all users if they want to see it. And yeah, the downside is it's more work for staff.
While I like the idea of the transparency that publicly viewable edit histories allows, on some of my sites we have a lot of potential legal issues (defamation mostly), so there are plenty of occasions where I would need to ensure that nobody was able to see the edits.
In addition to defamation, we also get posts which breach our laws regarding offering financial advice, and there are also privacy issues to deal with - members posting private information about other members. Often it's just an innocent mistake, but sometimes malicious too - either way, edit history would need to be hidden.
I guess an option at edit time of making the edit history hidden for certain posts would get around that - for posts where there is no legal issue we could have the transparency of the full edit history visible to members, but for certain posts, the edit history (or part of it) would only be visible to moderators.