In most of the classic Superman canon, Clark meets Lois, Perry, Jimmy, and Lex in adulthood when (or after) he gets a job as "a mild mannered reporter for a great metropolitan newspaper". Up until this point (depending on the version of the comic book you are reviewing), Clark has never publicly used his abilities before, or at least never in a way that could possibly be connected to Clark Kent. The costume is the "mask" that lets Clark use his powers to help people while allowing Clark live an "ordinary" human life. Nobody (OK, Lois always does) makes the connection between Clark Kent and Superman.
In Smallville, all that has been turned upside down. Everyone meets and gets to know Clark years before he puts on his tights. Except on rare occasion, Clark has never worn glasses and doesn't appear to have vision problems (aside from occasionally lighting something on fire with his heat vision). Lex Luthor used to be Clark's best friend and the day Clark shows up in Metropolis wearing his famed blue, red, and yellow "fighting togs", it'll take more than bright primary colors to keep him from seeing that Superman is just Clark in a costume. No pair of glasses, no matter how nerdy, will effectively keep Lois from seeing that Clark and Superman are the same guy. No one is going to be fooled because they all know what Clark looks like too darn well.
Let's take another example: the season 7 finale. Lex learns that "The Traveler" is really Clark Kent. In his attempt to take over Clark and rule his powers, he discovers and visits the Fortress of Solitude in the Arctic. Lex has finally put a long list of clues together that started when Clark saved him from drowning in a car accident seven years ago. All of the tons and tons of weird, odd, strange, and bizarre events that have clustered around Smallville finally add up. Unless Lex gets brain damage and forgets the last decade of his life, how in the world will he ever not know that Clark Kent is Superman? Don't tell me that the WB folks will kill off Lex. They can't. It would be like Batman with no Joker or the Fantastic Four with no Doctor Doom. It just can't be done. All superheroes need arch villains to balance the equation. Lex is Clark's arch villain.
How about we consider some scenarios and forget about solving the puzzle for awhile. Yes, the Smallville writers have their hands full, but they created this mess so now they'll have to fix it.
- Will Clark and Lois be in love by the final episode?
- Will Lex show up to screw up Clark's life again with some evil scheme (and will he still know that Clark is the Traveler)?
- Will Lana show up one more time to let us know her fate (and in the comic books, she marries Pete Ross)?
- Will Perry White be the editor of the Daily Planet by the final episode?
- Will Clark learn to fly before the final episode (and will the mystery of why he couldn't fly before this be revealed)?
- Will Martha Kent still be alive at the end of the series?
- Will Chloe still be alive at the end of the series?
- What will be the fate of Kara/Supergirl by the end of the series?
- Will the series end in a cliffhanger?
- What will be the final scene in the final episode in the series?
As far as the last question goes, someone on twitter yesterday mentioned the same final scene I've always envisioned. Clark in a room/alley/other secluded place, responds to an emergency by opening up his shirt. We see the famous Superman emblem and know, as we've always known, that this is a job for Superman. Fade to black.
In other words, Smallville ends and Superman begins. A fitting ending and tribute. Of course, if Clark really did get "the costume" from his Mom at the end of season 9, that means he has to hang on to it without "officially" wearing it (yeah, he could try it on for size, just so we can have the thrill), for 22 episodes. In Clark's "dream", he's Superman in 2012 and the series ends in 2011. If the 2012 date (which matches the release date for the Superman reboot Superman: The Man of Steel) marks the first appearence of Superman in the world, then the final scene in the final episode could be Clark going into the Fortress, finally submitting to Jor-El's will and beginning his training, as Clark did in the original Superman (1978) film.
I don't have a crystal ball (or Kryptonian crystal anything) and I have no special insight or access to spoilers, so this is all just in my imagination. Consider this, though.
If it were up to you, how would you end Smallville? Comments now being accepted.