I agree whole-heartedly.
The film was a lot of fun, and a fresh take on what could very easily have been stale material.
My major complaint about the score (as heard within the context of the film, and not as a stand alone CD), however, deals with what I see as misuse of thematic content.
While some scenes are tremendously powerful - demonstrating, I am sure, that Giacchino does have a great musical talent - there is so much ill-advised use of thematic material, seemingly out of context, that it ruins the overall effect.
What I presume is to be called the "enterprise theme" (opening credits, when we first see the enterprise, etc...) is FAR too present, and particularly in scenes where the Enterprise and her crew are NOT the focus of the action (notably during the destruction of the Romulan vessel at the end).
There are many fine bits of scoring int he film, I don't anyone to think I hate the whole score or how it is inserted into the film. But there are far too many moments where the music is too "pompous" and cartoonish.
Add to that the orchestration has a tendency to a stale 2-dimensional style (very reminiscent of Hans Zimmer's orchestral style). There isn't enough actual orchestral counterpoint and the textures of the orchestration tend to be rather bland and repetitive, relying far too much on overly obvious devices (pounding drums, string ostinati, etc..).
The moment where all of this comes to a final blow, is the closing credits. Superimposing Giacchino's music over Alexander Courage's original trek theme only serves to highlight how dismal the orchestration is and how 2-dimensional the harmony and thematic treatment are.
I loved the film, so I would give the score a good rating purely because it is associated with a film I enjoyed.
If I were rating this as a stand-alone score, it would get a failing mark, for all of the above reasons.