You might want to ask yourself why. Clearly this anti-RMT measure is doing its job.
If they got rid of gathering fatigue they would have to significantly reduce the amount of items obtained per gather. So how would you feel getting one log per gather, or one iron ore per gather maximum? How would you feel having to mine or log for eight hours to get what currently takes three?
You simply can't have it both ways. No matter which method SE uses, there HAS to be a limit on the amount of items a single gatherer can bring into the economy each day.
SP on the other hand, that's an entirely different thing but I've already made my points on that. Get rid of half SP on fails, make it full SP and there's the problem with gathering fatigue solved. A quick two minute fix that makes a huge difference.