Usually Uldum and Vashj'ir are the best place to farm large quantities of gold. But if you're in it to make money, i suggest farming the highest profitable herb and selling them. When it comes to Nodes/hour, it all depends on which profile you use. Nodes take 1 min to respond and if your farming profile is too short, you're probably gonna be flying around waiting for the nodes to respond. If you get a profile that covers a larger area of the zone you're farming, then you're most likely to farm herbs faster. In addition, other botters are a factor too. After running your first couple rounds in your profile, you might notice your node/min decreasing.
What i like to do is farm heartblossom for about 30mins, then hearth and farm another area(like twilight highlands) for about 30mins(until all the nodes respond in deepolm) then return to deepolm to farm again.
You dont have to do this for uldum or vash'jr because there are plenty of nodes there so you dont have to worry about their respawn times.