AJ / Arthur Joseph / Arthur Junior
Yes, the new Aquaman was not very popular. BUT, it was because he was stealing the spotlight from the original Aquaman.
Imagine if Arthur Joseph was reintroduced as the long lost son of Aquaman, Arthur Junior (who was probably retconed out of existence in the New 52) - I think people would like him more.
If was de-aged just a little bit, he could work well as a sidekick / partner, using the classic Blue costume (he was seen wearing it on Batman The Brave and The Bold TV Show!) and a new codename, maybe even Aqualad ( But only if we can find some better name for Kaldur to call himself! )
- Real family relationships could be develop since Aquaman and Mera are AJ's parents (but unfortunately DC doesn't like it very much...)
- Lack of power diversity, he has basically the same powers as Aquaman (But that could be resolved if they give AJ a different power, like mimic the abilities of any sea animal - just as Animal Man does, but only with sea life)
- Now AJ would be stealing the spotlight from Aquaman's other sidekicks, like Garth and Kaldur.
What do you think?