But then I thought about it, and the URL thing is a red herring. That's not what they really want -- that's an implementation detail. What they really want is the ability to play something from their local server on their TV. This is totally do-able in the Apple eco-system. The URL thing is exactly what you don't want. Who wants to type a URL into their TV using their phone as a virtual keyboard or not? (Which the AppleTV + iPhone combo does this great too...)
The best option is where you could "cast" any video/media you're watching on a phone or computer up to a TV. The AppleTV + iPhone (or Mac) combo does this great.
Also, just to understand, what does Roku get out of blocking your ability to potentially see non-DRM content? Is Neflix going to pull their app if Roku starts displaying urls?