I don't think its too controversial. Rather Kishi is tying up loose ends and moving the story along very quickly. This made everything that happened a little overwhelming. Essentially, everything in the series has pushed the story to these points, but instead of spreading everything out over a number of chapters, Kishi put it all in one.
1. The war arc is coming to an end soon. It is down to the entire world versus Madara and the Juubi with Kakashi and Obito fighting in another dimension. This is just the natural progression of the story.
2. Minato hasn't mastered anything. He merely is using the chakra that he took from Kurama on the night Naruto was born. The Reaper death seal sealed the chakra inside of him with a similar seal to the one he used on Naruto. I'm sure there are differences between Naruto and Minato's use of the chakra. One that I am almost sure of is that Minato's cloak is a one-time use technique, and once done, Kurama's Yin chakra will not re-accumulate in Minato. Kishi had to explain where Kurama's other chakra went, and he did that with Minato's cloak.
3. The barrier jutsus used by the Hokage aren't new at all. The Sound Four used a similar barrier to contain the battle between Orochimaru and Hiruzen, and Darui's unit used one to contain Tsunade's boyfriend. The extra part is just a Ten-Tailed version of the jutsu Naruto used in his internal battle against Kurama.
4. I'm gonna give this one to you. Sakura's development as a character and a shinobi just doesn't make sense. She can barely function in combat when compared to the other heavy hitters in the series, and yet she is now standing there with Sasuke and Naruto, ready to square off against the most powerful enemy in the series so far. She may be planning on using some sort of supporting technique, but that wouldn't explain what she said and did in the chapter. She still needs to build up chakra to release her new technique, and if it was some supporting role, she would just sit back and do so. It seems as though her new technique is offensive in nature. This is a huge change in Sakura's role in the series. From day one, she was a supporting character with little to no combat potential, and now she is being compared to Naruto and Sasuke. It just doesn't make sense.