Unlike CP, which is fairly well done, GP has very few reasons to worry about increasing it. Outside of a few skills which require more GP than the base maximum(and learned at a high level) you don't need more GP, because the regeneration rate is the real limiting factor at most levels.

I don't think the problem is the standing regeneration though, but rather you should gain more GP on each successful harvest. Normally when you are actively gathering a node, your normal regeneration stops and instead you gain 5 GP for each successful whack. I think GP gains per node should be considerably greater, probably 25. This would allow more regular use of skills, either one weaker skill per node or a stronger one every few. Gathering really should be more interactive and I think this would help a bit.