I don't think they took into account the bot farming which causes a huge disparity between normal users farming and them getting 6mil gold/hr.
There is also evidence of duping on the Asia servers already requiring a rollback so. So people are actively trying to exploit the system and there are not enough checks in place.
Just to clarify the item dupe was caught quickly and no rollback was needed, they were able to track the item that was the basis for the dupe and all the clones and remove them.
