Hi Finnian,
Thanks for the comment and requirement, it is a great idea and something that esri is considering for our field apps. Currently, straight line navigation (or compass/bearing directions) this is not in apps like Navigator nor Collector nor Explorer. Today, as work-around's you could:
1) create network paths between the locations, and create a custom navigation map (in Pro) for routing on those paths with Navigator. Navigator 2.0 supports navigating on custom data created in Pro.
2) use Collector's blue pulsating dot (indicating your current location) to orient yourself in the field, in relation to the points in the map.
The above however isn't exactly what you are requesting. We do plan to look into designing and developing this in our field apps roadmap.