2) Lex Luthor
Speaking of Mongul, there’s an even bigger Superman enemy who we think should turn up on Supergirl – the Man of Steel’s nemesis himself, Mr. Lex Luthor. Season 2 of the show introduced the female members of the Luthor clan – Cadmus chief Lillian and her actually nice daughter Lena – but it’s time we saw the dark horse of the family.
One of Supergirl‘s traits is that it, generally speaking, restores the more classic tone and approach to the Superman mythos that the current DC movies are lacking (the exception is the show’s radical reinvention of Jimmy Olsen). Just like Tyler Hoechlin’s Superman is a throwback to Christopher Reeve, then, the show could give us a classic Lex Luthor, one who’s more Kevin Spacey and less Jesse Eisenberg.
If it were up to us, we would bring back Smallville‘s Michael Rosenbaum to play the part. However, that might be a little confusing considering his past history with the role (and he might feel like he was cheating on Tom Welling by facing off against Hoechlin’s Supes instead).