The great wuxia novelists' works are considered classics of their genre, and are loved by millions of fans the world over. In the view of most of these readers, these works are perfect as is...or, if they need improvement, they should be improved upon by the original writers, not by a secondary party. You almost never hear of anyone who's read a wuxia novel and then seen the adaptation (or even seen the adaptation first, then went back to read the novel) argue that the adaptation was better. It's safe to say nearly all fans believe that good adaptations should stick to the novels as closely as possible.
So why do the TV/movie producers feel compelled to make sometimes drastic changes to the material when making adaptations? These guys are wuxia fans too, right? They probably loved reading the original novels too, and are probably well-versed in the details. Why, then, does it seem impossible for a TV/movie adaptation to adapt a novel "straight"...with no changes from the novel?