Note that learning the Xianglong Palms by no means elevates you to Great level. It didn't to Guo Jing, even after he learned all 18 he needed the inner power boost from the Jiuyin text to get close to the four leading martial artists. Same with other practitioners such as Yelu Qi, the various Beggar Clan leaders and so on.
The rationale for why Kang Long You Hui is so powerful is quite profound and I don't think any of the explanations have done it justice. We need the assistance of someone who has a deeper understanding of the ideas contained within the text: Huang Yushi, please...