A few points since there seems to be confusion about Minato's KCM. Bijuu Mode or Kyubi Chakra Mode? It's Kyubi Chakra Mode, the same thing that Naruto had before Bijuu Mode. You can compare the seal markings, they're identical to KCM. When Naruto goes BM the markings drastically change. Why did he get it so easily? It's not because he's just Kishi's golden boy and perfect, he got it because he only has Kurama's Yin chakra, he doesn't have Kurama's will. So he didn't have to fight Kurama like Naruto did, he could just access the chakra like Naruto could after he stole it from Kurama. How powerful is he? There's no doubt that this boost his abilities drastically, but this is NOT Bijuu Mode, it's just the initial Kyubi Chakra Mode. We've seen the difference in BM and KCM. He shouldn't be able to use any partial transformations or Bijudama. Basically KCM just boosts his base stats, makes his Rasengan more powerful etc.