One disappointment is that's not geared towards media playback or apps like netflix. In the interviews, they mention relying on the web-based versions of apps. Unfortunately, they often come with artificial limitations (limited streaming quality) by companies such as Netflix.
I'm fully aware of that. Imagine sideloading mobile applications on the steam machine. It's very hard to get a platform that reasonably respects your privacy. Smart TVs and boxes like Roku go out of their way to invade privacy. I'm not sure about Apple TV. It would be nice to be able to use the steam box as a replacement _officially_. I have no doubt there will be some sort of community effort.