I would be happy with GP coming back at the same level it was when you switch classes. I can see that maybe they don't want you to be able to switch classes and switch back to replenish your GP, but when you are waiting on a unspoiled crop spawn, the current system prevents you from doing anything useful, unless there happen to be lower level nodes that you can farm nearby.

If you didn't gain GP by switching but also didn't lose, we could run some quests or craft while waiting for a node to spawn, and switchback when when the node spawned without penalty. It would be a big improvement.