It's kind of sad to me that people are down on the game because it looks "boring."
I understand now why every trailer for everything is super bass, explosions, dramatic music, explosions, jumping off of things, explosions, and a large something or other roaring at the camera while it shakes and blurs up and smash cuts to title.
The Team Ico games ooze atmosphere and history. They are as much about calm and stillness as they are the journey of the characters. We praise Dark Souls and Demon's Souls and Bloodborne for how little it holds our hands with narrative, well, Ico and SOTC took that to huge levels. Everything about the game world is left to you inferring its history from the environment and the superb art design.
Some games you just have to sit down and get lost in. I remember the first time I saw Demon's Souls, I thought it looked horrible. Horrible framerate, horrible movement/controls, clunky combat, mediocre visuals, etc, but I ended up taking a chance on it and buying it. And man, I was so wrong. I fell in love with the game, and it, Dark Souls, and Bloodborne are some of my favorite games.
I can't speak to how The Last Guardian is going to play, but if it's anything like Ico or Shadow (it looks to be leaning more towards Ico), it's going to be immersive. It may not be flashy as far as setpieces go, but the art design and atmosphere alone looks on par with their previous work. That is to say, fantastic.