Hehe, why not?
I've tended to stop writing out the super-common special abilities, like WotC began doing with scent and blindsense and so forth. If you think we need it, I'm fine with adding it, though.Should uncanny dodge get a line in the Combat section? Otherwise, Struthiomimus seems pretty well finished.
So giving them reach like a polearm would be appropriate--they can't attack adjacent targets.The weird thing about this beasty is that although it had a long neck, there were only 12 long cervical vertebrae, which means it wasn't able to coil its neck tightly like, say, Plesiosaurus. So while it can bite at targets 10-15 away, it can't do so at targets right next to it unless they are so large that part of their bodies are reachable.