I might be in the minority here, but I think the entire boardwalk area should be completely redone/rethemed; from Superman, to the new coaster, pretty much all the way down to the games lining that path by the Carousel.The rides you just mentioned, the Ka replacement (I assume the entrance to it will be where GLs entrance was), a rethemed version of Superman, and an entire landscape overhaul should be a great start in reviving the boardwalk.
I don’t know that it will happen at all, but if it does it’ll definitely be a multi-year project. I really love what Kings Dominion has been doing with JungleX, and my hope is that Six Flags starts leaning into doing more cohesive themed areas like this. Considering the exciting plans they have lined up for Great Adventure, I think this area could significantly benefit from a massive multi-year revamp with the new coaster as its anchor. Doesn’t necessarily have to be jungle themed. But this area is definitely most in-need of something like this, with the entire lakefront stretch from Skull Mountain down to BBNP following not too far behind.
Luckily flying coasters are very flexible theming wise, so I’m sure whatever the new coaster is themed to, they could easily find something in that realm that would fit Superman. But I think the Boardwalk is definitely going to be the hotspot for most of the park expansion in the next 5-10 years. I’d definitely love to see at least 2-3 new coasters in that area alone over that time period.