D3 is by far more played out. There is absolutely no replay value. D2 is my jam. I actually just started logging back in last week after the new ladder reset. You wouldn't believe the amount of juggalos always playing on the us east servers.

Your both flat out wrong about D3, they have added alot of content to make replay better like nephlam valor, key wardens, PVP, and most importantly oobers.  My guess is you either havent given it a fair shake, or you did when it was brand new. Have fun playing D2 its a solid game for sure.

My level 60 (30) Barb can hang on monster power 10 which is the highest difficulty, but he dies pretty quickly if I let my auras lapse.  

I agree with you on the inventory, but we all had mule characters in D2, idk how that is much different unless you are splitting hairs.

Where D3 fucked up was the auction house.  Plain and simple.  Instead of looking for new items in dungeons, you sell all your shit you find to go buy the gear with stats you want on the AH.  Im personally glad they are getting rid of it, but am making a mint selling my old gear now that im getting tired of playing it.  Well honestly ive only reaped about 20 bucks, but i invested 0 so thats a win if you ask me.

You can't. Item sites sell more gold than you could ever get, for a cheaper price than you would find it worth. 

So unless you're ready to grind for 300 million gold and sell it for about $5 or somehow you can amass 20 billion and sell it for a couple hundred you won't be getting paid. 

You can however sell it on JSP for forum gold(fg). d2jsp.org

The current scale of worth is 1 million in game gold for 2.5 forum gold. $10 worth of forum gold is 290fg, which equates to about 116 million in game gold. So you would in theory make more money selling it on JSP, but you can't trade in your forum gold for real cash. You can use it to buy items and shit on the forums. JSP also covers like 60 other games that you can use you forum gold on.