Seems like a good enough reason to me. I love that shot!I can't think of a single good reason for it to be built planetside other than to have Kirk sneak in to look at it
"Because it looks cool" or "because it'll be a neat scene" should never be a reason to make a scene.
That's Michael Bay thinking, there.
Well, let's put that scene into some context, which can be deduced from the trailer.
The trailer places the journey's of Kirk and Spock in parallel. Both are trying to become something special, something more than they are. Kirk is a self-destructive young man. Spock is the product of two worlds, human and Vulcan and must make a choice.
In a wider context, there is something each man loves. Apparently, Kirk's Dad, the one thing he loves most, is taken away early in his childhood. Spock's love isn't Vulcan as much as it's his family - his father and mother. For each, there's a choice - a choice to choose what they will love, a moment when they are confronted with the sight of that thing.
For Spock, as we know from TNG and the movies, that which he loves expands over time. His parents represent, in many ways, the two forces that lie behind the Federation, Earth and Vulcan - which is parallel to the Kirk-Spock relationship itself. Spock makes the choice to join Starfleet - a choice to try to reconcile the opposing parts of himself? Maybe, but perhaps it begins with him embracing the more emotional part of his heritage. After serving with Pike, he begins to embrace the idea of wanting command for himself - but he's too young too human for that, to unstable to be a captain. When he sees Vulcan threatened, he begins to expand his love beyond himself, rather to the wider scope of the Federation. He begins expanding his journey to be something special...so by the time he is old, he returns to save the Federation, not just his crew (as in TWOK). He's seen a future that threatens everything. To do that, he needs Kirk, which gets us back to Kirk's journey.
Kirk's journey is one from self-destructive adolescent to Captain of the Enterprise. He'll need Spock for that. Kirk is also a womanizer. Sure, he can love a woman like Carol Marcus, even father a son, but that's not Kirk's first and true love. No that has been and always has been the Enterprise. This scene isn't a scene for the sake of being "cool," it's Kirk's first look at his true love, and it's love at first sight. He's on Earth, and she's on Earth. She'll be launched into space, and he'll join her there. So, it's only natural that he see her, not in space, but on Earth, being built. This is a highly symbolic scene. It's his first sight of his true love, and it's also symbolic of things yet to come. As she is built, he is built. She is built on Earth, she is built on Earth. She will take him to find his truest friends, and his best friend, Spock.
And this brings me to a bit of speculation. I have a suspicion, with the sighting of what appears to be Spock's time ship in the trailer, that this film may end with Spock's true death. IMO, he'll give his life in order to save Kirk and his crew - a direct nod to TWOK, but this time, Spock is not to be resurrected. I should think that would be a fitting end for Spock, giving his life to save the people he most cared about - a second, and final time - which is likely the reason Shatner's presence wasn't requested.