As you know, I was on a thread supporting the 9MM. I am of the opinion although Speed, Accuracy and Power are the three items needed to be a good shot, overall accuracy is usually the most important. Any student has to learn the basics and concentrate on their accuracy before moving to the next step which should be power. Move from the .22 target to the defensive rounds and then work on the speed.
Diligentia-Vis-Celeritas
Shot placement.
Shot placement.
Shot placement.
If you are proficient in the above, using a .45acp also helps. ;-)
Exactly what I did, although I still need work on speed.