I think this is a really solid move. This gives OSS contributors a lot of flexibility. You could set the limit to 0, and manually add contributors. You could set it to 1-3 to allow people to get their foot in the door. But the de facto limit today is infinite, which is spammed. Imagine if GMail did this! If I don't whitelist or reply within `n` emails, youre done. I would KILL for that.
I think, amusingly, the right thing to do for most open-source projects is to have each pull request summary and code read by an agent that just reimplements itself from a description of what the code is intended to be. Other people's code is not particularly valuable anymore.
There are some projects where you can provide a PR and they'll just reimplement and I think that's probably adaptive to the world where PR's are cheap and reviews are expensive.
There is also the solution of: No merge requests, just feature wishes and bug reports. All code is written solely by the maintainers (with the help of LLMs).