Re: The Best, The Worst of Smallville
I would assume that they wanted to make Clark somewhat normal, so the audience (presumably made up mostly of people of average intelligence) could relate to him more. However, taking his powers into account, he really should have been the smartest guy on screen, possibly only rivaled by Lex Luthor (until other non-human entities start showing up).
But that would require a lot of clever writing. And it would kill the high school angle. It would have been interesting though, to have actually seen a super intelligent Clark, like in the comics, perhaps building robots, traveling the world and absorbing cultures, and learning languages. But obviously they also had budgetary concerns. And unlike the comics, Clark couldn't fly as a child.
Really, Smallville's Clark Kent was pretty half-assed. Lacked the superpowers and the super intelligence.