The concept is bad because you don't want that property; you want a mutable data store with privileged and unprivileged access.
There are different categories of data. Data which refers to the the chain itself must be immutable, I agree. But data that represents the content of articles posted there does not.
> The concept is bad because you don't want that property; you want a mutable data store with privileged and unprivileged access.
You do want that property for some categories of data. You don't want unaccountability in who can update articles and what changes they can make, but you do want the articles to be changeable.
What this provides is to prevent an organization from being corruptable. A government or powerful corporate entity could pressure wikipedia into changing an article to suit their purposes, and wikipedia could stone wall and refuse to comment on any changes they made for that purpose.
If it was on a blockchain, and an editor was pressured into making such a change, the community would be able to directly vote that editor out and get the original content restored.
What you're really talking about here is a change of governance model to allow editors to be removed more easily.