The passive has to be balanced for all DoL classes. Right now it's bad for MIN and BOT but decent for FSH, so it is currently unbalanced.
Simply increasing the value so it's useful for MIN and BOT would still make it just as unbalanced because then FSH would be benefiting way too much from it.
A proper solution would be to change the trait entirely so that it did something like restore a certain amount of GP (10?) after finishing a node or catching a fish with a rod.
