10man multigathering stats for the last 30 days
tl;dr 10man herbalism/mining = 1 million gold every 7-14 hours on a low pop realm.
I leveled 10 Demon Hunters in pre-patch, and I decided to make them double-gatherers, as my other characters did not have any gathering profession. There was enough time to level these gathering professions from 1 to 700 before Legion went live, and I heard that both herbalism and mining nodes will become shared, so you can harvest the same node multiple times (currently 10 is maximum taps on each node)
Now a tad over month have passed by from the Legion launch, and I took a peek on my TradeSkillMaster statistics, and the results surprised even myself. In Legion, I have spent 1-2 hours per day for gathering. There also have been days that I didn't log at all due to other activities.
Last 30 days
Leystone Ores sold 31,952 ( 692,281g )
Felslates sold 17,775 ( 937,745g )
Starlight Roses sold 10,964 ( 1,720,001g )
That alone sums up to 3.35M liquid gold per 30 days.
Divided by 30 days = 111,667 gold each day.
Divided by 2 hours = 55,833 gold per hour (GPH)
My characters have The Nightfallen honored shoulder enchants for Tinged Mana-Packs, which may contain flasks, potions, enchanting crystals, shards and dust and what else. It's a nice bonus for multiboxers, as each mob gives a 5x chance to trigger that pack.
Everything summed up, currently I'm making a million gold every week (7-14 hours in total) on a low population realm, where I thought the markets were pretty much dead but apparently I was happily wrong. I've decided to put all the other WoW activities on a side, while the herbs (especially starlight) still sells for 150-180g each herb. Nuts, huh?