See, and I look at it from the other angle -- the Clark of this story would never be able to lead an army against Nor the way canon-Clark did. He's just way too damaged. Not to mention, he wouldn't have the support of "his people", which is what ultimately convinced Clark to fight when diplomacy didn't work.
And even if this Clark did end up fighting against Nor's forces to save the Earth, he'd either not be able to kill Nor at the end or would have a complete emotional breakdown (a la Lois's breakdown over almost killing Moyne), if he did so. I'm not sure he'd ever be able to recover from something like that.
Kathy