Originally Posted by The Valeyard
It's more about logic. We have to believe that these characters aren't idiots. Kal needs to do something drastically different with Clark in order to make him be divergent from the public Superman identity.
He didn't really do anything with it in that last scene. No change in voice or mannerisms. No change in hair. Etc. It was hard to buy.
It's not about logic, though. It's about suspension of disbelief and the beauty/inherent sadness/relevance of someone being overlooked because most people can't or don't look below the surface of a person. That's always what the concept has been about.
It has never been about LOGICALLY being able to fool people with a pair of glasses, a different hairstyle, slouching, etc.
And you can apply logic to anything. That doesn't invalidate the strength of the actual concept as a storytelling device.
As for them not doing anythng with it...Clark Kent in that final scene didn't exactly scream "Superman" to me. So I think they did "do something" with it, albeit in a more subtle sense than we're historically used to. We just haven't seen Clark's whole "plan" for blending in. Which makes sense, since that sequence is essentially just a tease to say "See, Clark has a plan for blending in".