I think the topic of surplus/fatigue is simple psychology. The surplus system is, ultimately, a rested exp system. Except the way it's implemented is punishment. Someone back on page 1 mentioned this exact same thing but if they flipped it around and made normal rested and surplus normal, it would virtually be the same system we have now, just worded in a way to make people feel rewarded rather than punished.

Punishment via challenge is one thing, having to defeat that difficult boss is punishing but in a positive way. Intentionally restricting people openly is the wrong type of punishment and should never exist for a customer buying into a product. Either they need to flip it around so that it's virtually the same as it is now except put into a positive light, or they just need to do away with it entirely.