User blog comment:Xilinoc/Ch. 679 - THE END/@comment-18753817-20160623222914/@comment-24769684-20160625144443

The thing is, a good antagonist should be more powerful than the protagonist at first, so that the protagonist may realistically gain the strength to overcome them. Thus, the burden on the author is to develop both the protagonist and antagonist so that the protagonist's eventual victory feels well-deserved.

Aizen was OK at this, because despite some BS from the Hogyoku, he was basically a culmination of Shinigami, Hollow, and Arrancar, three races that Ichigo had fought before. He didn't do anything other than what was par for the course for the three races. Ichigo knew how to match up his strength to that of the three races, and caught up to Aizen, although Final Getsuga Tensho be damned.

Now, Yhwach. As the progenitor of the Quincies, he should be the pinnacle of Quincy strength, the pure opposite to Ichigo and the Shinigami. But Kubo has been so liberal on deciding what Quincies can do that he has made Yhwach into something more like God. Yes, Yhwach does have connections elsewhere, but should he not be a Quincy at heart? Instead of someone with a flawless power that Ichigo has no chance at overcoming at all, because he is simply not suited to realistically deal with this kind of power? With this arc, the sheer discrepancy between the growth of the protagonist and antagonist was extremely poor, because Yhwach can go so high out of bounds that there seems to be nothing for Ichigo to strive to.