GPS technology in the ball?

Perhaps the game could be played out in a virtual grid, Tron style, where every movement of the ball could be mapped electronically and ruled on instantaneously; the players could be suspended in a large harness where their every motion is translated to that of their electronic avatar, a bit like them big robots off of the opening credits of the Sky coverage. There would be no need for a ref, a stadium, a crowd or Eddie Hemmings, and cheating would be literally impossible. Craig Charles could present it, with Sir Killalot doing analysis of the accuracy of the algorithms; Robot Superleague - the kids would love it.

I think that would only tell the direction of travel of the ball relative to the ground and we would have exactly the same disagreements we have now.
Its impossible for a ref to be in the best position to spot all infringements all the time so perhaps the answer is for TV "experts", fans, coaches and players to stop analysing every decision to the nearest millimetre and for us to accep that refs, sometimes get it wrong ( but then who doesn't?)

It's quite possible to detect a forward pass remotely. As you say some kind of position sensor for the ball would tell you where it was and from that you can work out everything else. If you measure the position again a short time later you know which direction it's gone and also how fast it's got there but that's not really helpful. Once you know the speed you can then work out the speed are short time later which gives you the change in speed or acceleration which is what you need. Any acceleration of the ball in the direction of the opposition's posts at the moment the pass is made would indicate a forward pass. You'd have to sync the data with the video to check a bit like the clip meter for cricket.
Alternatively, we could stop listening to sky's incessant search for controversy at every decision and realise that the human refs actually get it right almost all the time despite what the partisan fans think.