The seemingly astonishing power Shinichi had displayed earlier was, in the end, mostly a bluff—an effect he had deliberately put on because he had no other choice.
It could scare people the first time it was used, but its flaws had already been exposed by the end. The next time they fought the Cloud Ninja, the enemy certainly would not fall for it again.
Shinichi's real abilities amounted only to floating in the air and throwing fireballs and ninja tools. They could be quite effective on an individual level, but they could not turn the tide of battle.
Not even Minato, Jiraiya, or Uchiha Fugaku could do that. One person's power was ultimately limited.
Given the current gap in strength between Konoha and the Cloud Ninja, unless someone like Senju Hashirama or Uchiha Madara arrived, only the Tailed Beasts—or rather, Jinchuriki capable of transforming into Tailed Beasts—could influence the battlefield.
But Kushina was not a perfect Jinchuriki. Though she could use the Nine-Tails' Chakra, she had forcibly taken that Chakra from the Nine-Tails. At most, she could achieve Nine-Tails Chakra Mode from the original story.
Not the Nine-Tails Chakra Mode that Naruto and Minato possessed.
Her only way to transform into a Tailed Beast was to lift the restrictions on the Nine-Tails and let it take control of her body, sending it into a rampage just like Naruto when he lost control.
But the consequences of doing so would be as uncontrollable as the Nine-Tails itself. Leaving aside whether they could suppress it again afterward, once the Nine-Tails controlled Kushina's body, it would undoubtedly make Konoha's ninja its first targets due to its deep hatred for Konoha.
Or they could send Kushina alone to fight the Cloud Ninja, but the outcome of that was equally obvious. She might inflict tremendous