It still comes back to why does it matter? Obviously, disappointed or not, Paramount saw enough in the performance of Star Trek Into Darkness to decide to make another one. Going so far as to hire Orci as a writer/director before having a falling out.
Because if Paramount was disappointed in the film's box office it means they'll try to fix the problems of Into Darkness in the sequel.
And I do believe that Into Darkness was a disappointment. Sure, it was no bomb, but the film made less money domestically than the original even without taking into account inflation. That's not a good sign. I'm sure Paramount has looked into why that is and have plans to improve numbers for the sequel.