I do feel that queue times are an unreliable metric with which to assess the popularity of any ride, let alone one like Curse. There are far, far too many factors that affect queue times to come to a judgement about popularity based on the queue times alone.
With that being said, I will offer a further suggestion about why Curse’s queues are reasonably short. Could the return of the 6th seat possibly have had an impact? It probably hasn’t, as the cars are rarely filled anyway, but 6 is a marginally nicer number than 5 (as it’s an even number), and the 6-seater cars might be more conducive to accommodating large groups, or putting, say, a 4 and a 2 together.