I'm struggling to follow this thread... are you proposing an alternative, simplified version of the laws, or is this your interpretation of the current laws?How about:
A player who is in contact with anything in touch is considered to be part of the touch line until they resume the FoP.
If a player was in touch they aren't back in the FoP until no part of them is in touch (ie a foot in the FoP and the other raised is in)
A player can jump from the FOP and play the ball before they land in touch.
Assuming Red played the ball last:
If blue a player is in touch, and they deliberately play at the ball before being back in the FoP, blue took it out, so red LO
If blue a player is in touch, it hits them and they didn't deliberately play at the ball before being back in the FoP, red took it out and so blue LO.
Doesn't matter if the ball crosses the line, only if it lands in touch or someone who is/was in touch.
I umpire netball at a state level and the requirements for netball throw-ins/off-court are much easier to interpret/officiate and the players to understand. Its also vastly easier to pick up and even during fast games the mental workload in working out off-court decisions - which happens vastly more than in a game of rugby - is much lower.