So, on desktop, when you click cogwheel -> "Advanced" -> "Video stats" - you will see advanced stats, such as the estimated latency, the number of skipped frames, the FPS, and so on.

Would be good to see the server the broadcaster is uploading to, and the server you are downloading from - would greatly help with reporting and/or solving connection issues. And since it'd be under "Advanced", the average user wouldn't see that, so it wouldn't generate a lot of complaints.