Just a question...
Why would ANYONE draw a line on the shaft at address??
Is this a precursor to the question 'Why would anyone draw ANY line?'...
Back to your question, I'm not afraid to admit that I have drawn this line on my screen when analysing my own swing. At impact, I used to get the club much closer to this line (or along a plane closer to this inclination). Personally, seeing the club steeper suggests to me that I am getting underplane and act as corroborative evidence with the shots I am seeing (high rights and low lefts). Then I load up Never Hook Again, add more carry, swing left of the wall and the club looks flatter through the ball.
Were I tracing a straighter plane line through the ball and hitting better shots, I wouldn't worry about the handle being higher at impact. I'd love it! Are there better ways to be analysing this? Maybe. Comparison to the shaft position at address is only one indicator I would use.
So. Without 3D or Trackman, what should we be looking at? Are there a top five key lines, circles or anything for two-dimensional cavemen such as myself to look for? (I know now that getting back to the shaft plane from address will not be one of them...

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