Maybe its because XAJH have too many weak characters that's considered to be good enough for Dongfang Bubai. We really NEVER see DFBB fighting one one one with a opponent near or above his level.
If you have the chance to see DFBB fighting against a powerful being outside XAJH era, who would it be?
Sweeper Monk? Xiao Feng? Xuzhu? Yang Guo or even Shi Potian? Or others?
I personally would like to see DFBB squaring up against Yang Guo, it would be hell of a match...