Unless I am missing it, I'd like to see the ability to turn on trailers and the preroll video on the Xbox one. Like the web utility or even on the IOS devices. I've created a nice theater environment and would love to have it be like going to the movies.
This would be a nice feature..
The XB1 app doesn't yet support Play Queues or continuous video playback. Both are required for this feature. When they're in place, the Cinema Mode will be possible.
Other features currently absent in XB1 can be found here: https://support.plex.tv/hc/en-us/articles/204103423-Where-is-feature-X-
(along with some reassurance that we do intend on getting all these features into the app, eventually!)