I don't like it.
What we have now is too tough on the attacking side. Players being called offside when it was never intended that they'd be offside if only by 1cm.
What Souness is suggesting is too far the other way. Allowing players to be basically a yard offside, as long as they leave a little behind and the defender has a little poking forward.
I think somewhere in the middle would be better. It would be more in keeping with the original rules and spirit. If you're about level, you're fine. More than a foot ahead, and you're offside.
Of course it would mean having an arbitrary distance (say, the average width of a player, or 1 foot, or 30 / 40cm. But so what?
PS - Poll options too limiting.
What Souness suggested would have the laser-lines working behind the players rather than in front, so wouldn’t actually change much.