I've read some comments in internet where they refered to a supposed answer of the creator of Saint Seiya stating that all saints were equally strong. Is this true? This doesnt seem to be what's shown in the series and what fans in general think is saints like Shaka and Saga are usually ranked higher.
Unless there's an interview I'm not aware of, Kurumada never said that.
What he said is that what he really cared about was trying to create them all cool and powerful, but even him cannot say which one is the strongest.
You can check that here.
Just thinking at the manga and anime stories, I can say that Saga has much more power that all the other Gold Saints. I am saying this because he is able to force most of them under his will. He is also able to control a couple of puppies saint while he is still in the Grand Master Hall. Then he is also able to confront and resist to multiple attacks from some gold saints together.