I really don’t see how Nightwing isn’t A list. If your talking comics importance his role in the titans for multiple decades is some people fav part of pre 52. If you mean name reconition and popularity how about how he has been constantly represented in multiple animated shows and is often the primary focus of whatever show he’s on even when it’s about a team (Teen titans, Young justice, etc).
Hell as soon as he was annouced for this game most people knew who he was and he’s been one the most picked characters. I’ve seen more gameplay of Nightwing than I have for Superman and Nightwing is a stance change character which usually very unpopular.
I don’t agree that a character needs lesser versions to be A list and even then you could consider the other robins as his ripoff versions. They even had Damien as his actual sidekick while Bruce was “dead”.
I think the fact that people are complaining about the lack of “underrated” characters says alot about the ones confirmed already. Imo characters like Cyborg, GA, NW are more known than they given credit for.