There are other specific parameters in football, such as whether the whole of the ball did or did not cross the goal line between the posts...or any line. There's another rule, although I haven't seen it enforced lately, which is that if at any point in time the last phase of play the ball touched the hand or arm of an attacking player, regardless of whether it was "deliberate", a goal may not be scored. An illegal back pass to the keeper is pretty straightforward to enforce and I think a fantastic rule. Other examples? How about the requirement that a player who takes any free kick may not touch the ball twice. How about a keeper not being allowed to use his hands or arm outside the box. The ball must be placed on the quadrant in the event of a free kick. The rule against spitting at an opponent is defined by specific parameters -- spitting and where the spit is directed. You may spit at the turf, but you may not under any circumstances spit any other player, not even your teammate. A player, nor manager, may not push or make any physically aggressive contact with any of the officials. It's an obscure rule and I've only seen it enforced once, but a player may not leave the field of play unless expressly authorized to do so by the referee. I'm sure I can come up with another half dozen examples of specific parameters concerning how the game is played.
In other words, the offside rule is hardly the only rule that sets specific parameters about how the game is played.
With that behind us, I will grant that any new definition as to what constitutes offside will yield absurdities such as the offside call against Coventry. When you look at that photo closely, the most you can see as offside is the knuckle on the left pinky toe of the Coventry player. If I were to define this in percentages of body weight, at least 99.9% of the Coventry player was onside, assuming that his lefty pinky toe knuckle weighs half an ounce. But did he really gain anything remotely like an unfair advantage over United despite the fact that AWB had him in full view and that he was offside, if it all, by less than a quarter inch? I don't think so.
Where you really have me at a disadvantage is the impossibility of perfect clarity with any other alternative. The next best idea is the daylight idea, which holds that if there is observable daylight between the forward and the defender then and only then would the forward be offside. For example, if the knuckle of the left pinky toe extends beyond the blue line of the last defender, he's onside. But if he's half a body length behind the defender and you can see, actually see, green turf, between the front half of the defender and the back half of the defender, offside. This can work, and it would vastly improve the game from the remorselessly tactical shit we've been seeing the last few years, but it would not be a perfect solution to the problem of absurd offside calls.
