Sure Vixen can project more animalistic traits...she's a hero and I'm all for her, but she doesn't make my top 6 list.
Starfire I understand.
Beast Boy I understand.
Raven I understand. Raven was mad popular in IGAU1.
Ares, Shazam, Zod, Zatanna, I really understand.
But why Red Hood? because of one movie that came out in 2010...horrible comic book series with not much good ratings despite having Starfire and Arsenal by his side. We're talking about possibly the worst Robin of all time, the worst leader of all time and a guy who got his ass kicked by another Robin, the original.
Make Red Hood an alt skin for Deadshot. Real talk. They have the same move sets. That way we can have Red Hood and have room for 9 more other characters.
Give me Slade and give me Dick. The best of the villains and the best of the heroes, these are guys with an actual resume in DC comics with a huge and deep following for each character. Both guys have been featured in their own comics without relying on a supporting cast.