Thia reminds me of my first lesson with Bert.I'd say all parts of the game rely on a good stroke. If you can't send the cue ball where you intend consistently, not much is going to work and it will be really hard to get better.
I remember watching someone teach a banking system to a relative beginner. The beginner had a stroke that looked like a seizure -- he usually hit the object ball on the correct side. I'm not sure why the beginner wanted a banking lesson or why the "teacher" thought it would be useful.
I told him I needed to work on my 9ball break.
He threw some balls on the table and asked me to run them out.
After 3 failed attempts he asked why I would want to break better when I can't even run out.
I will just be making it easier for my opponent to run out if I break better.
He then said he would not show me how to break better but if I wanted to take lessons to learn how to play the game right, we could get started -or something to that effect.
He was right.