I agree. Giants sounds much better. They might've changed the title for copyright issues though, especially for merchandising purposes. The New York Giants are an example of a brand that wouldn't be happy with Disney registering the word Giants. Similar reason behind Day of the Death changing its title to Coco. Additionally, they probably wanted to distance their film from the recent live action Jack and the Beanstalk, so I'm sure they avoided that title on purpose.
Yeah. Pixar can make you feel emotional very easily, and that's something I really appreciate about their films. But when reading the description of this particular film, I just felt that they just tried too hard to find lots of emotional situations to throw around and hope they can make the audience feel emotional themselves. As I say, that's not necessarily a bad thing, but does every Pixar film really have to make you cry? I hope my opinion on this film changes once we get some more footage.