Using the slide release is no more of a "fine motor skill" than pressing the trigger, the magazine release or using the sights.
In order of speed-
1) Slide release with strong side thumb.
2) Slide release with weak thumb.
3) Racking the slide.
Using the slide release with the strong thumb is only marginally (.10- 15 second) faster than using the weak thumb, but is more prone to pre-release of the slide.
Using the slide release with the weak thumb is very fast, extremely consistent, and repeatable in daylight, at night, and under stress.