It's so artificial than some nameless joe who breaks to the open heaven at rank 7 can reach rank 9 no problem, as a matter of course, only by mastering a single great dao out of the dozens. Yet Yang Kai can have every single great dao topped to his current limit, yet he can't reach rank 9 simply because he was forced to break to the open heaven at rank 5. The system is truly artificial and bugged. Yang Kai should release a patch to fix it.
Also, I can't be too thrilled about the discovery in that river since it's of no benefit to Yang Kai himself, personally. Like I said earlier, the story has more or less forgotten the daos in combat, it's all about punching and beams of featureless energy. The soul damage needly was a welcome addition back then, but it has got nothing to do with daos; Yang Kai can use it due to the soul warming lotus. He did suddenly develop his own river of time technique to slow down enemies, so I guess the author did receive some feedback along the lines of my complaints, but I'm still far from impressed.