CBeebies Land has done a fine job in getting guests to visit... Indeed, Disney don't seem to have a problem getting the guests, and they don't have much in the way of big thrilling coasters/rides...
With correct marketing and quality, you can get guests to come and ride anything you build...
Hex and Duel never really have queues because of their throughputs (Duel) and people not knowing what's inside (Hex)... Hex is a weird one because it seems to rather confuse guests as to what it is, especially with the two pre-shows, which is a shame because it's the best dark ride we have in the country (apart from when the curtain fails to work)... Sub Terra I can't help but feel has no re-rideability either, which doesn't help it's cause, as well as being pushed towards the high thrill level of dark ride...
A high quality dark ride could easily change perceptions of them... Indeed, an over-reliance on marketing surveys and the like is really what's making the Merlin parks rather dull and lifeless more so than anything... The parks need to be thinking ahead of themselves, and building something that guests didn't know they wanted until they had ridden it...