Got your attention, didn't it
I'd like to start this off with a comment that I personally don't really 'believe' the argument I am about to make, and I don't think the conclusion was JY's original intent either; however, I think the logic is pretty compelling. I don't think it is ironclad, or unsinkable...but I think the evidence on 'my' side is stronger than the evidence against it. More than anything else, this is an exercise in analysis and logic.
Interested? Watch this post.
THE PREMISES:
Premise #1: Guo Jing's internal energy, at any given point throughout LOCH or ROCH, is always inferior to Zhou Botong. This is because they have the exact same internal energy base; Quanzhen energy, mixed with Jiuyin principles. This is a very powerful combination of internal energy, that is said to grow no matter what, even if you are just sleeping, and that the more internal energy you have, the faster it grows. However, Zhou Botong started out at a higher level than Guo Jing, and we know for a fact that as of the end of LOCH, Guo Jing's internal energy was still lower than Zhou Botong. Therefore, unless Guo Jing practices martial arts and cultivating his internal energy much more than Zhou Botong does (an assertion which has no textual evidence and, in fact, is contrary to their respective characters), Guo Jing's internal energy should thus always be inferior to Zhou Botong's. And, due to the nature of Quanzhen energy, the growth of his internal energy should also always be inferior to Zhou Botong's as well.
Premise #2: Guo Jing was, at the time of the fights he had with Jinlun Guoshi, on par with Jinlun Guoshi. This was stated multiple times by Jinyong, and I think we all know this by now. In their exchanges, it was stated that Jinlun Guoshi was stronger, but Guo Jing's palm technique was exquisited; hundreds of stances would have to be exchanged before any sort of determination of superiority could be made. Now, pay attention, because this is important: At the time of the fight with Jinlun Guoshi, Guo Jing had no problems directly taking on Jinlun Guoshi's powerful blows.
Premise #3: Guo Jing's external martial arts did not improve, or substantially improve, during the 16 year gap. I see this for a simple reason: There is no evidence at all to suggest that he developed any new martial arts, and he himself admitted that his XLSBZ "has not seen action for a number of years", by the time of Guo Xiang's birthday. If he's developed nothing new, and if he hasn't been actively using the old, how much can his external martial arts improve by? Of course, all martial artists improve with time and experience, but there is nothing to indicate Guo Jing's external martial arts improved by much at all (or any more than any other martial artist at his level would).
THE EXTRAPOLATIONS:
Extrapolation #1: Based on the first two premises, if we accept them as correct, we can conclude that at the time of the first Heroes Gathering, where Guo Jing and Jinlun Guoshi fought, Zhou Botong could also directly take on Jinlun Guoshi's powerful blows. If Guo Jing could take on Jinlun Guoshi's palms, and Zhou Botong's internal energy was higher than that of Guo Jing, there is no reason why Zhou Botong could not take on Jinlun Guoshi's palms as well. This is important.
Extrapolation #2: Jinlun Guoshi's internal energy improved more in the 16 years interval than Zhou Botong. Based upon extrapolation #1, Zhou Botong should have been able to directly take on the palm attacks of Jinlun Guoshi, pre-16 years; however, we know for a fact that he did not dare take them on post-16 years, and instead was forced to fight extremely defensively, using his Vacant Fist, Kongmingquan to deflect Jinlun Guoshi's awesome power. If Zhou Botong should have been able to take his power head-on pre-16 years, but is not able to take it on post-16 years, then we know for a fact that Jinlun Guoshi's improvement in internal energy was considerably greater than that of Zhou Botong.
Extrapolation #3: If we accept extrapolation #2 to make sense, then based upon extrapolation #2 and premise #1, Jinlun Guoshi's internal energy therefore also improved more than that of Guo Jing in those 16 years. We know that Zhou Botong has more internal energy than Guo Jing; we also know that Guo Jing's internal energy should not grow faster than Zhou Botong (or at least, there is not a shred of textual support for this). Therefore, logically speaking, Jinlun Guoshi's internal energy growth should be more pronounced than his.
Extrapolation #4: If we accept premise #3 to be correct, then post-16 years, the ratio-level of Jinlun Guoshi's external martial arts, compared to the level of Guo Jing's external martial arts, should be no worse than it was pre-16 years; there's not much evidence that Guo Jing's external martial arts improved much, and although there is a little evidence which Jinlun Guoshi's may have improved (witness the new martial arts he passed down to Da'erba), there also isn't enough to show a substantial change, much like Guo Jing. So we'll call their external martial arts a wash, ratio-wise.
THE CONCLUSION:
If we accept the above to be correct, then this means that the relative level of internal energy of Guo Jing and Jinlun Guoshi post-16 years is now more in Jinlun Guoshi's favor, whereas their relative external martial arts remains the same. This, then, would indicate that Jinlun Guoshi, who was previously only on par with Guo Jing, has now surpassed him.