I've seen a lot of problems with D3 - not all of them seem to stem from the existence of the RMAH. Piss-poor endgame is one of these problems... to think they'd actually expect a decade-old concept like "repeat the entire game on harder mode" to fly with today's RPG players (whom many weren't even SPERM when Diablo 2 was at it's height) is beyond logic or reason. :P
It's not like it really matters how long people stay in D3, being a one time purchase
Just like D2, players who don't enjoy repeating the game to improve their characters will leave and those who want to devote the time will stay
But unlike D2, D3 has a lot of competition and it's unlikely it'll get anywhere close a similar cult following
You asked what is pay-to-win in WoW, and there was a quite clear post on that
There is a PvE "race" in WoW, that D3 doesn't have. It's mostly coop, so buying gear has no negative impact on others... well I'm certain there will be complaints unless Blizzard adds PvP with those with RMAH items separate from those who doesn't, but yeah.
I could just imagine if WoWs most hardcore guilds could buy BiS items and just fly through content. Even regular guilds asking their members to buy trinkets and weapons to speed up progression..
Nah, in WoW this system would be utterly destructive to the game
No, just no, Ive already spent enough on D3, and it would completely ruin realm economies because of their size, 9/10 items on the AH would be for real life money and most likely extremely overpriced, I'm certain the only reason it "works" in D3 is because of the Ah size, its not like you can choose a realm to play in D3, so it makes the Ah much much larger.
1. Wow is a subscription based game, and Blizzard generates their revenue from that sub fee + box sales. D3 is not a sub based game, and once they sell the box to someone, the only way they have to make any more money is by taking a cut of the RMAH sales fees.