In the short term I don’t know if a B&M hyper would have had a bigger impact than the Swarm. However, since they get such poor feedback on Trip Advisor and the biggest source of complaints is the queues, adding several really high throughput rides over a period of time would have a benefit. Two parks that really show this are Canada’s Wonderland and Europa Park.
Canada’s Wonderland isn’t the highest rated park in the world by any means, but it does get a huge number of visitors spread over a small number of days. In 2019 Canada’s Wonderland was the 13th most visited park in North America, getting more visitors than Cedar Point and Magic Mountain. Canada’s Wonderland also has a very short season. On peak days it gets Disney sized crowds. To help them cope they’ve got two B&M hyper coasters (one’s a giga) and a B&M dive machine. These are probably the highest throughput thrill coasters you can get, without having ‘special’ features like duel stations and continuous loading systems. The three B&M aren’t necessarily the most ‘interesting’ rides from a creative stand point, although Leviathan is incredibly thrilling. But they do help the park to manage their crowds.
Europa Park gets a lot of stick over its omnimovers. But having several rides that can be staffed by one or two people and do 1,300 guests an hour plus, has served the park really well. Even on the busiest days there are substantial rides you can go on with virtually no waiting. If Thorpe Park had a B&M hyper coaster that could do 1,400 guests and hour and an omnimover that could do 1,400 guests an hour, then I think their feedback would see an improvement.