The only downside to what you're asking for is that the game can be pay2win (unlegit ofc).
Not to mention in most MMOs with raiding gear etc being at the top it doesn't take long to get geared enough (praise the gods of RNG) but to have BiS (best in slot) on the hardest raid difficulty takes months, and you only get 1shot a week.
All in all I think devs saw how D3 was on release with the AH, it wasn't a game, it was a spreadsheet buy low -> sell high trading simulator.
The problem with MMOs is that all in all, they're pretty much the same game, some tweaks, slapped on new artwork. (Yes some may be tab-targetting and some may be action combat, but it all boils down to the same concept)
TL:DR
Devs want you to play for your gear instead of trading / 3rd party shops.
edit:~ I think the game you envision is just not out there. Sorry
This post was edited by mii_ruru on Mar 31 2015 06:50am