CMV: If someone is fired, they're entitled to a reason

I favor at-will employment, the idea that an employer can fire someone at any point for a wide latitude of reasons (with some exceptions for discrimination, retaliation, or public policy) but I do think there should be a legal expectation of a reason in writing.

That just seems right. One immediate benefit is that it's harder to fire an employee for illegal reasons if some kind of justification has to be provided. Others do not need to agree with the justification.

People often get fired for things that have nothing to do with the quality of their work, like budget cuts or mergers resulting in redundancies, so in many cases, the explanation is innocuous.

Obviously, people could be fired for things they would rather not disclose (IE- if they've been late too many times, and customers complain they smell like a brewery) so there can be an option for someone to waive an explanation of why they were dismissed. If the reason is something embarrassing to the company (they had to fire someone to make room for the boss's nieces, an important client had a nightmare about someone, etc.), the big-shots could also pay employees extra to agree to waive a right to a public explanation to avoid embarrassment.

I've had this discussion in other forums and one worry is that employers may weaponize this system somehow, but I think in the long run, employees are more likely to benefit from greater transparency. The businesses benefit at their expense from opaqueness and a lack of accountability, covering up their own misdeeds and hiding information that would allow employees to negotiate.

The only downside I see is a bit more need for paperwork to document something, but maybe I'm missing something, especially from people with experience in management.

What are the reasons employers shouldn't be expected to provide reasons for dismissing someone?

* Edit- A technical point is that perhaps the title should read "if someone is fired, they should be entitled to a reason" since this is about how I would like the law to be, rather than any kind of explanation about what the law currently is.

The reasons should be somewhat specific, and it would be provided in writing. An employee would be allowed to share it with whoever he or she chooses.

It wouldn't be enough for an employer to say that someone's a bad fit with the company culture, but they'd have to give a reason (or several reasons) why.

An employer could say their intuition told them to fire someone, but there may be professional repercussions to that explanation and there's potential trouble if any evidence disproves it.