I think the people discussing the title here have misunderstood Oda's priorities a little bit. Heaven and Earth would have made a great title, it's dramatic, it's epic, it represents the strongest action scene of the book, and most of us here love shit like that. Hell it was my best prediction. But to Oda, far more notable than the action and drama is the way Luffy, in his Lucy persona, has managed to inspire the population of an entire nation. Oda loves the upbeat scenes, where the Dressrosa citizens have been driven by Lucy to escape from and push back against the birdcage and have a hand in saving their own lives. Oda loves their absolute faith in him, and the way they stick to it, counting him in even as Doflamingo lashes out against them. We love the action, and we remember that best, but this is what Oda loves, and that's why its represented in the title. And yes, I do strongly believe that he gets to choose them.
Regardless, I'm loving this one a lot. It's dynamic, the colours are nice and some great scenes from the book are represented. The layout, with a villain's face filling the background and Luffy winding up his final attack front and center echoes volume 65, but that's cool because that was a sweet cover as well.