The height of the bore axis is a factor I believe, but for different reasons.
First, the bore axis height has virtually no effect on pointability. Grip angle has the most effect on that. A 1911 with an arched mainspring housing points high for me. With a flat mainspring housing it is perfect. Both have the same bore axis height.
A difference in bore axis height mainly requires that you hold the gun slightly higher or lower. You raise or lower your whole arm slightly. This is no different than shooting at a target at a different height.
A difference in grip angle requires that you angle your wrist upward or downward. This can be uncomfortable for certain shooters and certain guns, and a gun that is uncomfortable to hold can be really uncomfortable to shoot.
The main effect of a high bore axis is muzzle flip, and I believe muzzle flip is a major cause of flinching. For the same gun weight and ammunition load, the recoil of the gun with more muzzle flip will feel worse.
Also, muzzle flip makes rapid fire more difficult, although it should have no effect at all on the first shot.
-