If I were to write the next season for the series, I would start off by resolving, or rather complicating the myths behind Lex's resurrection. Either way, Smallville would continue to be the battleground between good and evil, between superman and supervillan, and between justice and unreined quest for power. I also expect there to be some twist on the romantic relationship between Clark and Lois.
Smallville: The Complete 10th Season and The Complete Series are both available on DVD. Catching up on missed episodes couldn't be easier!
Disclosure: I have been hired by Warner Bros WBWord division to raise awareness for "Smallville."