As someone who read and liked the book, this trailer was a huge turn off for me.
The book is campy and fun. TIE fighters as limos at a fancy ball, Ultra Man battling with Voltron, random TMBG references. This movie is being marketed as EPIC BATTLE FOR THE FATE OF THE WORLD with AMAZING VISUALS and LOTS OF FEELINGS. Looks like it was written by a bunch of suits in a board meeting more interested in calculating return on investment for the license deals. And I love the Iron Giant as much as (if not more than) the next guy, but it's jut plain the wrong era of animation.
The one good sign is that Spielberg is involved. His success rate on blending profit with storytelling is higher than most. I'll still give it a chance on home video, but it's not looking theater-worthy.