I agree with Carlsson and Nocturnal,
I find the toggle control really difficult to use and not intuitive at all.
Having played games like Asteroids and Kerbal space program (perhaps not the best examples) I found their press and hold controls gave more of a thruster feel to the controls and feel more natural to use as a pilot.
Alternatively being able to type in or set a bearing would be also cool and perhaps would give more of a submarine feel. However I understand that could be technically difficult to implement.
An option in the menu would be a great idea to cater to different sets of players and something I would like to see.
Worst case I think it would be possible to implement press and hold in custom hardware but is kind of a last resort.