Everybody has their own pace and you have to find the pace that works for you. As long as a fast paced player is still exhibiting good fundamentals, a good smooth stroke and staying down and still through the stroke, the amount of time one takes between shots is not that critical. Some players can see what they need to do extremely quickly and others are just way more deliberate and are comfortable taking much more time planning out the shot and where they want the cue ball to end up, and the spin and speed necessary to get it there, even before they even begin their pre-shot routine over the ball.
My pace is on the slower side, but I will say this - A fast pace player may be able to get in twice or more as many shots per hour in their practice sessions as a slow paced player. Over the long haul, that could be extremely valuable in shortening the number of years it takes them to reach their potential.