Allowing a user to decide the buffer size would greatly improve playback while on a mobile network. While I understand that when using a larger buffer it would relay the video feedback on for example changing channels, it would improve the more normal path where a user is watching a movie or channel and network drops in and out. By allowing a user to decide on a larger buffer it would help to smooth out the drop outs and the video would not pause as frequently. I believe the browser versions allow for larger buffers but adding this feature to mobile apps would greatly enhance the viewing experience. (on channel change you can jump to live and through buffer away so user sees more immediate channel change)
A second request involves Bluetooth audio. Some Bluetooth devices (mostly lesser quality devices can add a slight lag to the audio which causes a lip sync issues. If a user adjustable setting was added to allow a user to delay the video enough to sync the audio that would allow the play to be used with more Bluetooth audio devices.... The setting can be smart to only come into play if the player recognizes that audio is routed to Bluetooth (not sure if its always detailed if not a user selected switch (turn on delay and how long a delay to use can both be added)
Hopefully these two items could be added, I feel the first one is the most important since I believe it would affect many mobile users, where the second item is more limited to fewer consumers.