"I hope that I gave you some enjoyment over the years, and that you found my portrayal of Lex Luthor to be satisfying," [Rosenbaum's] statement says.
To me, Lex was the best thing about Smallville while Tom Welling was gaining experience. More interesting than Clark's coming of age was Lex's descent into true evil. You can't have Lex and Clark battling very long before it gets old, but there is no equal to Lex as a foil.
The eighth season will probably be the last, and the only thing more I want to see is Clark and Lois growing closer, building the chemistry they'll have in the future as rival reporters who fall in love.