Go look at Archeage that tried to do this. Took the hackers less than a month to make it useless. EVE is unique because the game is equally mean to players and bots. Want to make goldfarmers lives miserable, do nothing but raid their ships and destroy their PLEX supplies. Have an Axe to grind? etc.
These kinds of systems only work in PvP-centric games because that puts an actual reward for the PvP system, not just griefing because PvP attracts sociopaths.
Everyone, please do not encourage "revenue" mechanics from F2P games (this includes things like Gachapon, I'm looking at you Gold Saucer.)
What will happen is that the Gold farmers will instead buy up all the "plex" resources and then sell them at whatever rate they want it to sell for so they spend less time actually farming, and more time stealing peoples accounts to charge "plex" on. That is what happens in these other games that have tried to duplicate EVE's plex system. One account gets broken into, the "stored" credit card information gets used to charge as much as the card will authorize, they sell it in the game, and then give the gold to their gold farming accounts before the stolen account gets discovered.
I wouldn't even consider it unless every player was required to have an authenticator.
Here's the thing:
EVE is a "hardcore" PvP game, which has the equivalent of perma-death. The only other game that did this was Wizardry Online, that SOE shutdown because "lack of interest" , which was also a hardcore PvP with perma-death, and sanctioned inventory theft. It also had a "plex" type of system.
WoW is ... I have no idea because I've never ever played it. AFAIK WoW, Star Trek online, Star Wars TOR, all tried to variations on subscription/freemium hybrid models because they want to keep players coming back. But in actuality, what makes people leave subscription games has nothing to do with money and everything to do with content. Freemium games never have to improve the content. Indeed most freemium games only offer very trivial cash shop item updates as patches, and the major content updates are bi-annually. The rest of the time you're just grinding to get the BiS gear so you can faceroll over the new content.