It's a strong section, but I wouldn't say necessarily any stronger than some other albums - Unconditionally and Birthday let it down for me personally, Unconditionally because it's a bit of a buzzkill in the midst of some big pop songs, and Birthday just because I find it to be one of her weaker singles.
Roar, DH, Legendary Lovers and Walking on Air are all great - Walking on Air particularly, I feel has been very underrated and could have made an amazing single.
I think the first half looks that much better, because of the second half, which is really nothing to write home about, but the strength of some of the material on the first half makes that insignificant.