This is what I would do:
* hire a platoon of mercenaries with the gold from one mission
* send the mercenaries into the WoW world to kill everything while I sleep in a tent for 8 hours, guarded by my friends
* gather all the healing potions as my share of the loot for opening the portal
* hire more platoons of mercenaries so that they can sweep the dungeon faster and go through more missions in an 8 hour shift
* experiment with different worlds in order to maximize the number of potions harvested
* use very large worlds when I go to sleep, and many small ones when I'm awake
* make do with Hummers to begin with
* acquire Hueys for deployments, UAVs for surveillance, and warthogs for firepower
* offer the mercs million dollar bonuses for every special forces soldier they can recruit
* gradually switch to special forces troops as older guys retire
* let them retire filthy rich so long as they understand the special forces guys are going to hunt them down if they ruin a good thing by blabbing
* upgrade my army to laser pistols and rifles as acquired
I would make everything as systematic and as fast as possible in order to harvest as many healing potions as fast as possible. Including an electronic system with RFID tags for automatic computerized check-in of soldiers before closing the dungeons. Including workers with lift equipment to get all of the loot out as efficiently as possible. Including prepared empty crates to put healing potions in.
Think about it. Since a soldier can run 4 miles in 36 minutes, my army could easily fan out into a circle of 12 km in diameter, kill everything in their way, loot everything in sight and come back to the portal on troop transports following behind them all within an hour.
The platoons would deploy in a star formation, one platoon going north (straight out of the portal), then another north-east (clockwise), another east, then southeast, and so on until the 8th platoon went north-west. THEN 8 more platoons would go in between the first 8 platoons to fill in the pattern. They would use gyroscopic compasses to make sure of direction. And lastly, the troop transports would follow.
It's almost 200 men with communications and fire support, assuming they go on 2 missions a day every day that's an army of 2400 men I'm employing. Plus another couple hundred for logistics, surveillance. I would acquire a lot of land for this naturally.
Assuming there's 1 healing potion drop for every square 100 meters on a side then (pi *4^2) square miles * (1 per 10000 square meters) > 13,000 potions. And 13 000 * 24 * 365 = 113 880 000. That's enough healing potions to supply the entire world.
Less than 3000 soldiers replace most of the doctors and nurses in the world.
And makes for a business with net personal profits to me of 11 billion to 110 billion USD. And after having done this for a year or two, I would petition France, Russia and China (the nuclear powers on the UN Security Council) to not only give me citizenship but also ambassadorial status so that whatever laws of the stupid country I'm in can never touch me.
Yes indeed-y, there's a lot of benefit to bettering the world.