Brick,
If by 'spade stick' you are talking about the circular grip type things then a very old and brave sim instructor told me these were that way so that when you had your hand shot off in a dogfight to could "stuff the bl@@dy stump through the hole and still control the kite"
Sounded plausable to me at the time.
I always used a similar scenario to argue against side stick controlled aircraft, at least with a centre stick you stand a good chance of being able to fly with the left hand if you've been shot in the right, not so with a side stick a/c.
Tarnished