The Golden Wheel Monk is generally acknowledged as being the equivalent (or perhaps even superior) to the Greats in terms of inner power, but inferior to them in actual fighting techniques.
I wonder if this might be the direct product of the Golden Wheel Monk having trained his martial arts in isolation.
East Heretic, West Poison, South Emperor, North Beggar, Central Divinity, Old Mischief, Gwok Jing, Yeung Gor, even Kau Cheen Yan...over the years, they all had each other to learn from and test themselves against.
By comparison, the Golden Wheel Monk spent decades in isolation in Tibet. We don't know what kind of sparring partners/opponents he might have faced during those years before he first emerged in the Central Plains during ROCH, but it's doubtful he was practicing/testing himself against fighters who possessed Greats-level techniques.
Perhaps that is the reason that the Golden Wheel Monk, despite coming into wulin with Greats-level inner power and otherwise decent techniques, found himself flabbergasted whenever he fought against the Greats. Having trained in isolation, the monk had no exposure to any truly elite techniques and therefore, was limited in his ability to cope with them. He was the equivalent of the A+ student who has memorized all the theories and understands them thoroughly, but lacks real world experience and finds himself frequently confused and at a disadvantage as a result.