When we open the File/Disc/Net/.. dialog we have a "Caching" option to specify the milliseconds of media to preload before playing it.
When the media comes from a network source, could it be calculated?
For example, with a checkbox "Automatic" near the "Caching" parameter:
1. VLC tries to download/downstream data for 1 second playing time
2. Based on the data transfer rate detected, establishes a new Caching time, never under 1 second
3. If at any moment of the media play, the cache empties and playing is paused, then calculate a larger Caching time to make less possible to pause again.