phatneff,
If you would change "without he/she him/herself
going to play the ball" to "without he/she him/herself
being within playing distance of the ball", then I would agree with your post 100%.
You understand the line of sight concept properly. It only applies to a player in the offside position and would fall under interfering with an opponent.
The best example is the US v. Italy game in the 2006 World Cup. FIFA put out a paper stating that the offside call against Brian McBride for blocking the goalkeeper's line of sight, even though he did not touch the ball, was the proper decision.