All sites need moderation.
The problem with SO's system isn't that questions are removed, but that questions are removed as slowly as possible, as publicly as possible, with as much drama as possible. Instead of having it instantly removed and taken elsewhere for potential question recovery.
Overall, public shaming as a moderator tool was a bad idea to begin with. Everything I've to say about the matter can be read here - Giving question feedback in private - a moderating system to reduce conflicts. A summary:
The main problems of SO's model:
Humans often simply don’t take kindly even to constructive criticism, especially not when given in public for the world to see.
The basics of leadership & keeping people motivated is to give praise loudly in public but to give criticism discreetly in private. This makes people far more likely to actually listen to the criticism and change.
Solve this by removing the question from the public eye and then give private feedback to the poster.
Deleting posts “as slowly as possible”. Bad questions get slowly grindedground down into the dust by down votesdownvotes, comments, close votes, all in public, really rubbing it in. And even when it sits there with 5 close votes and -10 score, it is still published for everyone to see.
Solve this by giving trusted users privileges to instantaneously remove a bad question from the public eye. This also minimizes friction as the question is moved away from those who haven't the slightest interest in helping new users.
“Bandwagon moderation”. The first veteran user who encounters a bad question and is willing to help out, often gives constructive criticism with links to help pages etc. So far, so good - that initial polite comment is often all that’s actually needed. Yet we have subsequent users arriving later, piling on further comments or repeating what's already been said. It stops being constructive and derails into what the poster might interpret as “you are bad”. And it creates a negative atmosphere for everyone stumbling over that post too.
Lots of such comments come from veteran users who are simply fed up by viewing the same endless flood of bad questions day after day. They actually don’t have much interest in helping the OP at all, they just want the crap question gone.
Solve this by not forcing regular users to view bad content, again by quickly removing such questions away from the public eye to a “quarantine” area.
SO's “crap hugging” policy of “we must preserve and publish all the crap ever posted and polish it until the end of time” is harmful. Similarly, when a question is closed since it can’t be answered and needs to be corrected by the OP alone, it is senseless to keep on displaying that question to the public.
It is much more important for the community to reduce negative criticism and low quality content than to preserve some unsalvagable homework dump for all eternity.
In addition, do not force users who just want to use the site to become moderators, by having a messy rep system that assumes that people with good domain knowledge automatically make good moderators as well. This simply isn’t true. A better reputation & moderator privilege system than the one at SO is needed.
Can this be fixed and implemented on SO? I don't think so, it's a lost cause. But a new site replacing SO could implement this and learn from SO's many mistakes.