I'm not sure about the cover, it's a bit too busy, a cover should highlight one moment in the volume that is pivotal in my opinion, having Kyuubi Mode Naruto, and bee off to battle, then the Eight and Nine Tails, the fist bump between A and Bee, The sealing Statue and finally Madara on a cover is too much information overload...and way to spoilerish for those who haven't read the volume before.
Agree. He's chosen to showcase some prime elements of the volume, each of which is a huge, dynamic creature. The result is a mishmash of images. The heirarchy of characters is muddled. Meaning your eye naturally wants to travels to the blank space of madara's mask, but it doesn't because your searching out Naruto. And to make him stand out from the other four character crammed around him, he's been brightly colored. But it only helps so much.
A lot of times, Kishi relies on black to create blank space in a group image: think Naruto's speech to Kushina about his friends. Sakura is set off against Hinata's black back and hair. So it creates an instant focus on the opposite lighter character, which is Sakura!
In this cover, it could have used more contrast. But everything is presented in the same colors. Darkening the three characters behind Naruto and Bee would have given the effect that the two were rising above the rest, jumping out of the page.
Anyway, it's not bad, and it does it's job of summing up what's inside. But as a standalone graphic image I think it falls short. There are several other covers that would make smashing posters, but this is not one of them.