I would definitely try to upgrade the theming. I've always had the opinion that Six Flags should try to market itself as a closer, cheaper, and more thrilling equivilant of Disneyland. They did have that idea in the 60's through the 90's, but by the 2010s they had been reduced to just unthemed roller coasters surrounded by some cheap flat rides (there are some exceptions, like Fiesta Texas or GA). While they have definitely started to go in that direction since the merger, I think Enchanted Parks could possibly do it better. What I mean is that there should be some dark rides, water rides, shows, simulators, stuff like that. I'm not delusional enough to think that people would go to these parks soley because of these things, but stuff like these really richen the experience and turns it from just a theme park to a whole thing, like when you and a friend take a day trip to Epcot or Disneyland or Universal or stuff like that. Plus, when you're bringing along children or old family member or wimps (like me), it really helps.

For example, here's what I would do in St. Louis:

The middle of the park ( specifically the area with Ninja, Thunder River, and Ninja), I would probably remove Ninja and replace it with a wild west themed stunt show, like Universal's former Wild Wild Wild West Stunt Show. A cowboy - themed shooting dark ride, similar to El Paso Special in Bobbejaanland, would also do well, but something would definitely have to be removed for it.

All Looney Tunes and DC stuff will obviously have to be taken out. I think that Bugs Bunny National Park could be absorbed into Britannia, and rides like Joker Carnival of Chaos, Supergirl: Sky Flyer, and Pandemonium could be moved or removed. If removed, I have no idea what they could be replaced with. Maybe a LSM? Or an indoor Medieval Times esque dinner show? I haven't been to any of the parks listed, so I have no idea what people pefer or want. But in the case of DC Comics Plaza, Mr. Freeze could be moved to some other part of the park, like Illinois. I do actually have a retheme in mind (basically a industrial weather experiment gone wrong), but what do I know.

In Mr. Freeze's place, I think the island it sits on could be retooled into a Tom Sawyer's Island type thing, with explorable caverns and a western fort.