So Ichigo will have to be stronger than all quincies combined to beat Juha. Well that is if all quincies die and Juha re-absorbs all his power. And becomes even more powerful, and that's bad. So ether way is a win win situation for him as long as the war is on.
Kubo will have to use the fact that Ichigo is a transcendent being and will be stronger than Juha somehow. Since Quincies can't absorb hallows, and stuff.
Also, looking forward to Uryu's resolve and his fight with Ichigo. I don't really see Uryu siding with the quincies that much. As Haschwa.. said he's regretting to follow them since he was just interested in revenge for his mother. Whatever, looking forward to their confrontation in the long run [a new day has started]... some Kenpachi and Rukia would be good in the next few chapters.
I think his downfall will be once he absorbs all the powers. Like Kubi said if he stops giving out his powers he will slowly go back to being deaf mute useless etc... so his power in itself is a big contradiction i guess his power is best meant to be lent out to people because getting his powers back doesnt really help him so it would be in his best interest to make sure the people hes lending his power to dont actually die.
Then again, he did just absorb Yama's bankai so this guy still is control.. hmm i guess if Yama's bankai can somehow be handled then the shinigami have a chance otherwise i dont see anything stopping Ywach other than maybe Aizen somehow plotting in the shadows.