That would be cool from an immersion standpoint, but my one concern with that would be that it would probably be a massive bottleneck throughput-wise.
Unlike Wicker Man, Duel was not designed to have a pre-show, and that ride system has a ludicrously high throughput. It'll become particularly ludicrous if 6-rider vehicles return as the concept art suggests; by my reckoning, a car passes a given point roughly every 10 seconds on Duel, which would equate to a throughput of 2,160pph with 6-rider cars!
By comparison, Duel's 5-rider vehicles made it get about 1,800pph at full capacity, so The Curse of Alton Manor should have a throughput around 360pph higher than Duel, in theory.
Back to the original point, though; the only way I could see a pre-show working is if it had an absolutely obscene capacity (I'm talking 100+ people, so a considerably larger room than Wicker Man's pre-show room, which accommodates 48, would be required) and a more streamlined batching process than Wicker Man's, as well as more space after the pre-show for the larger amount of people to wait in. The current indoor queue setup of Duel would not allow for this, so I don't think it would work unless they made drastic changes to the building interior.