What other structures would work for having a public forum for PRs?

I'm having trouble coming up with many that would be compelling enough to make that change, especially once you consider bad-faith actors in there (eg, I can't flood your git repo with my nonsense, because my code doesn't exist in your repository until the PR is merged)

I spend too much time doing archaeology to support squashed PRs, which eliminates a few alternatives I might otherwise suggest.