I'd like to see a "Squash pull request" button to avoid merge commits, clean up messy pull requests with WIP commits and changes to address review feedback, and keep master bisectable at every commit.
That would be awesome. The interface should be just like when you rebase and you get to select which commit you want to squash or keep.
Yes, squash would be awesome. I've had a number of cases where I had to d/l the pull request only to squash a long-running feature branch that is now ready for merge but has a lot of junk "work in progress" commits. It's be nice to be able to clean it up right in github.