Bungie hasn't put a new weapon into a halo game since h2.
And for the infinite flames that are going to come after this statement.
ODST SMG = Smg with silencer and acog attachment, a weapon attachment, not a new weapon.
ODST Pistol - hybrid cross between the h1 pistol (scope and damage) and the h2 pistol (large mag, rapid fire)
so, I'm not expecting anything new, but I have got hope for one.