Gu Long sometimes tends to go off the deep end in describing the most powerful martial arts in his novels...witness the "time-stopping" and "world-flipping" swordsmanship of Yin 13 in THIRD YOUNG MASTER'S SWORD.
Now THIRD YOUNG MASTER'S SWORD is a fairly popular Gu Long novel, but I don't think it's as popular as the LUK SIU FUNG, CHOR LAU HEUNG, and SENTIMENTAL SWORDSMAN, RUTHLESS SWORD novels. For better or worse, those three very popular Gu Long novels feature martial arts that are (for the most part) within the bounds of reasonable limits.
Is it a coincidence that the most popular Gu Long novels are the ones who feature martial arts and martial artists who, while powerful, are kept within worldly limits and don't perform otherworldly feats that seem beyond the scope of wuxia?