IMHO, a sequel wasn’t needed because there was enough of Clark shining through his Superman disguise. I wanted to “leave it to the reader's imagination”, as Lynn S. M. so aptly pointed out. Besides, I planted some seeds for Lois’s ulterior moves: her reconciliation with Clark, their investigation of Lex leading to the rebuilding of the Planet, her piecing things together (or not), etc.
You have a point, and it does work beautifully as a stand-alone with an implied ending/epilogue. However, there is of course a very obvious pick-up point for a sequel, should you choose to write one, and I'd love to see your version of what happens.
