I agree that GP could use a bit of work.

Someone else suggested +GP Regen as a materia option to increase its regeneration rate. I think that would be great.

I also hope that we can just regenerate GP in the background even if we are not in a gathering class.
Especially while waiting for unspoiled nodes, gatherers literally cannot do anything else except idly stand around and wait for the node to appear. We cannot craft. We cannot join FATEs or fight monsters. We cannot perform repairs. If we do anything that switches us out of a gathering class our GP gets reset to 0.

If it's working as intended, I guess they just want gatherers to go AFK while waiting.