The problem with attempting to bring the ride system back in a new form (from a marketing POV) is that the Pirate Adventure is so embedded in to people's memories,imo, that for any replacement to be worth its value in money to the park, it would ideally have to stand at least closely to the original in terms of quality, to be an effective marketing pull for the park. Otherwise I suspect it would forever be known as "the not so good replacement of pirate adventure". People still (bear in mind that it has been almost 10 years since Pirate Adventure has closed) bring up the "pirate ride at Drayton manor" and how good they think it was on social media, or when speaking to staff who work at the park. If a replacement dark ride of that size/scale didn't live up to expectations, I actually think it would possibly even put people off going to Drayton.
When we talk about using that space, we are essentially talking about a large signature ride. A ride that used to be on the parks logo in fact. And signature rides are often a lot like 'strong magnets' ( best analogy I can think of) for guests, in that they have the power of either attracting or repelling visitors to the wider park, depending on how good they are perceived as. People often judge a park based off of how good the signature rides are. One of the reasons why it was wise of Drayton to be very quiet about the ride's closure in the mid 2010s. And a reason for them to now be cautious about doing stuff with the space.
The optimism some people have about the ride returning is great, but we have to ground things in reality . It's extraordinarily expensive to operate a dark ride of that size. Let alone design and fabricate theming for it from scratch, or develop new lighting/sound/show control systems for everything inside it. And given the current state of the building, It's easy to imagine the planning costs and surveying costs for doing work inside the building being a huge issue for the park. I just can't see Looping wanting to build a ride of that scale, even if they can fix up the existing ride system.
To put it in to context; in the early 90s, the dark ride market was far more lucrative for theme parks. Hand built prop making was more cost effective in labour terms back then than it is nowadays, and it was easier to assemble large teams of ride designers (and for a ride like this, you would need a large group of people in a number of different disciplines). Raw materials costs were lower then too, and dark rides like Pirate Adventure are extremely dependent on these kinds of things. It's one of the reasons why opting for coasters is often a safer bet for parks nowadays. You don't need as much in the way of theming or effects built/maintained, and the risk to reward ratio is lower. The ghost train at thorpe park is a good demonstration of the risks of building a dark ride that doesn't pay off (and ends up being a huge cash sink for the park). It's why I can see why Gold Rush has been chosen (over adding a dark ride) in the former Apocalypse area. Coasters can rely on quick thrills, whereas dark rides have to be done extremely well for them to work effectively.
Think I may have said it before, but the best thing for Pirate Adventure is to let it sit there as a kind of 'shrine', and a reminder of the rides former glory, for all of the above reasons. Unless something can be built which lives up to the original Pirate Adventure, leave it as it is.