5. Nightwing (DC)
Who Is This? You probably know him as (the first) Robin, but the now grown side-kick to Batman would prefer you stop calling him that. At the age of 18, Dick Grayson, like many of us, decided it was time to spread his wings and be his own man; Nightwing now takes on the vile villains of Gotham City himself, finally living up to the apprentice role he was always destined for.
Why is this person a better choice than WW? As with some of the other choices on this list familiarity to modern audiences is a big selling point to why this character could turn into their own breakout star. Sure Wonder Woman had a tv show in the 70s, but it last aired 35 years ago. Batman has been the most prolific superhero over the past 20+ years, and Nightwing gets a big rub from that. He's essentially Batman 2.0; a little less brooding and relying less on technology as the Dark Knight, but in many ways he's a carbon copy the Dark Knight. This allows WB to use a familiar setting (Gotham City), familiar adversaries (Joker, Penguin, Riddler, Etc...), and even Batman himself would likely show up in a supporting role.
Who should be cast? For a while it looked like Girls star Adam Driver had the role, but its since been speculated that he's landed another highly coveted role, playing a villain in the Star Wars 7. Another option would be to continue to story of TDK trilogy and have Joesph-Gordan Levitt reprise his role. WB seems determined to make this is a clean reboot from that continuity, so his casting would probably only serve to confuse fans. One choice WB might want to investigate is recent Academy Award winner for Dallas Buyer's Club, Jared Leto, who also impressed critics and audiences in the classic Requiem For A Dream. At age 42, he is a little old for the role, but to look at him you'd never know he was over 30, and with his acting ability and resemblance to the character, he would be a great choice.