We had a Wordpress site at work, and ended up working around the staging issue by paying Pantheon for hosting. You can actually use git to manage code changes, and propagate changes to an intermediate staging environment before pushing to production; they also offer pretty simple tools to copy the database into staging from production as well.

All in all, it downgraded the Wordpress development experience from a hell to a heck. It was still unpleasant, and we still had a lot of pain points, but it did solve problem #3. (Although, I do have some other issues with Pantheon as well, but they're largely orthogonal to Wordpress proper.)