Again, critical does not appear to effect gathering skills in the open world. I have yet to 'crit' on a node.
It definitely is possible to crit on gathering a node, however it seems to be extraordinarily rare. I have been playing since day 1 of early access, and i have crit on manual gathering exactly once. It was a slicing node, and it gave me a blue-border money box(along with a normal white-border one). The blue box contained about 500 credits while the white only contained about 100. (it was on corusant, during the first week of early access)
If i knew at that time how rare it was i'd have taken a screenshot