With the change to Twig engine, integrating other site pages is more difficult. If you can add a way to create a new page (ala PageManager) that would be great for transitioning integrated sites or sites that have expanded content.
Should be reasonable, and will *definitely* be easier to do than before with code edits if you really wanted to.
We're using a nice framework (which I'm not sure has been formally disclosed yet) and Twig, so it'll be easy to extend a global template to another page.
I'm already hoping to get this in. It's an extremely useful feature for many sites and is pretty easy to implement.