They’d be better off putting an indoor dark ride next to / inside the Towers itself to replace Duel and complement Hex. Though with the Dungeons now, is a replacement haunted house even needed? Grouping all the ‘spooky’ attractions next to the Towers/Dark Forest builds on the park’s best asset.
Duel‘s warehouse-sized show building, plus the storage space behind it (I see old rapids and flume boats on google maps) would allow them to build something like an Intamin Blitz. Maybe even weaving into the woods too, like the broomstick ride.
However, that site might make for a better entrance to the park vs. Towers Street. Moving the entrance nearer the car park could allow them to remove the monorail and redevelop the existing entrance site instead. Planning wise, it might be difficult to stick an attraction if the lawns around the lake are listed too. I know that idea was proposed a while ago but I’ve not followed the industry news for years now...
Collectively, the hospitality industry will be holding its breath for a couple of years. I can see Merlin picking up the pieces of Sea World (minus the whales, please) if it goes bankrupt. Here though, it’s the constraints linked to the park which have given it some great attractions, but I hope any refurb takes time to rationalise the muddled layout we’ve got today.