While that is more plausible, it's still cliche as hell, especially because they never wrote garrosh and thrall to be this close in the first place. Garrosh becoming all whiney near the end was also laughable and at the time he had the right words for him. Burdening him down with doubt afterwards was mostly a cop out because metzen left and people were sick and tired of green jeses (which started in cataclysm).
That would be even worse story telling.. it's litterally stated that he has no use for the hammer anymore. Even in the books he cast it aside together with his armor.