Step 2 no longer allow any app that replicates abilities in the stock phone.
Not such a god idea. If Android has a browser, a "social networking" app (Google+), a music player, an SMS app, a maps app and so on, alternatives may still be useful (e.g. an alternative SMS app with spam blocking, an alternative maps source).
Or iPhone, which has Safari, forces all browsers to use the Safari rendering engine. Not so great if someone develops a better browser with ad blocking, a faster (or more standards-compatible) rendering engine, or some other features besides another UI with bookmarks sync.
Step 4 eliminate in app purchases.
Some in-app purchases are good. For example add-supported apps that allow to disable ads for a fee will keep settings, while the traditional solution with a free/paid version clutters the appstore and loses your settings if you upgrade, since it's a completely different and isolated app.