To say if the game design is poor depends on the goal in mind with the design.

In the case of a subscription MMORPG the design is often intended to make people grind endlessly in order to progress, for someone who has limited gaming time available that means they are subscribing for a longer period of time so more $$$ for the company. So from a company/investor perspective the design is great, for a gamer, especially a "casual" gamer who only has a few hours a week to put into gaming it's terrible.

Gold farming allows people for whom their time is worth a lot to skip the tedious stuff which might take them months to complete which means less subscription money.