Coincidentally, a very convincing case can be made that EQ gets you much further in life rather than a high IQ.
But honestly: IQ, EQ, CQ, AQ, BQ, NQ, FQ, DQ, SQ, MQ, PQ, and all that - as long as you have passion for, and fun in whatever you do, who really cares? Human beings love to categorize and package everything in their lives (including their brain and all aspects of their consciousness) into comfortable boxes with a clear label stamped on top to comfort their small personal insecurities and anxieties.
"Am I good enough?" "Can I ever be a good designer?" "Will a high IQ help me become a better game designer?"
These are the wrong questions to ask yourself, and will only kindle more confusion. Fear and anxiety hold many people back from fulfilling their true potential.
Do you really think Peter Molyneux, Hideo Kojima, John Carmack, Ron Gilbert, Sid Meier, Takashi Tezuka, and so on, ever checked their IQ to figure out whether they would have the potential to become good game designers/developers? Of course not. It's a ludicrous thought. They all created their games because they had a passion for games, and all of them shared the same urge to create their own games, all the while pushing the envelope because they could and had buckets of fun doing it.
Just create, and find your flow. Do not second guess yourself (too much , and create the game YOU want to create, and create it for yourself, and not for anyone else.
DO IT. And if (when) you fail, DO IT AGAIN. And have fun while doing it.
It is good to have an end to journey toward; but it is the journey that matters, in the end