What would the implications of a US constitutional amendment excluding corporations as persons and the constitutional rights that affords them?

Corporations are not granted the same rights as natural persons - they're granted some of the rights of natural persons (and some of those make sense while other are dumb).

Preventing corporations from operating as persons when contributing to political campaigns would be an absolute win for representation... Citizens United was a trash ruling by trash people.

Preventing corporations from operating as persons when interacting with the legal system would massively complicate our legal code and probably lead to a lot of awful edge cases where they could dodge liability for their actions. They are generally immune to manslaughter and some industries have dumb political carve outs (like firearms manufacturers having immunity to most product liability) but people's ability to sue, i.e. a paper mill after getting luekimeia relies on corporate personhood in our current system.

When we talk about "corporations shouldn't be people" we (I think it's fair to be generally inclusive here) are talking about their ability to donate to politicians and political causes.

Calling a constitutional convention right now would be insane. Republicans would take that process and fuck is up forever while pulling up the ladder behind them

Many different kinds of organizations are organized as corporations. Charities, newspapers, churches, etc. If the amendment was not carefully written, it could be construed to deny important rights, such as press freedom or religious freedom, to organizations that really ought to be protected. Similarly, the protections against unwarranted search and seizure or taking of property for pubic use without compensation should probably continue to cover corporations.

Really, the only problem I see WRT corporations having constitutional rights is the decision that political spending is protected speech. The other constitutional rights are generally not problematic.

So maybe something like this:

1. No person, whether natural born human or legal fiction, shall spend, donate, or otherwise make valuable contributions to any candidate or campaign, if said person is not entitled to vote in the election for such candidate or campaign.
2. Only natural born human beings shall be entitled to vote in any election.

The main reason why corporate personhood exists is to limit the liability of owners. If I run a company and a customer slips and falls, they can sue the company, but they can't sue me or my shareholders. Without any form of personhood there could be no limited liability. The customer would be suing me and the shareholders directly.

I don't think it would change much for giant corporations but that would be terrible for small businesses. I have a friend who makes his own stuff and sells it to people. He doesn't make much, a few thousand a year. He incorporated to prevent losing his house from a customer suing him.

I once worked for an Unlimited Liability Corporation (ULC). It's a corporation where the owners and shareholders can be sued directly for company actions. They took on that higher risk because the tax breaks that come with a ULC were worth it I guess. So it's not like giant corporations wouldn't exist if they weren't considered people, but it probably would hurt entrepreneurship.

The main issue Americans have with corporate personhood is the "freedom of speech" thing the US Supreme Court ruled on in Citizens United v. FCC. The ruling basically said corporations can't be prevented from giving their money to political causes because its a violation of the corporation's freedom of speech. That's specifically a US ruling. Other countries don't grant rights and freedoms to corporations.

As it applies to 1A matters like Citizens United, the result would be that wealthy individuals could still spend a billion of their own money on whatever speech pleased them as individuals. Failing to extend this right to corporate entities would allow the government to interfere with organizations coordinating the political speech of thousands of smaller donors. This isn't the win some people think it is.