Based on decades of professional game demo experience, and grad school teacher training, I would say that the best way to kill role-play enthusiasm for new players at a convention event is (a) pre-gen characters and; (b) rules info dump up front. Saddle players with those at the same time they’re supposed to be engaging with the unfolding story, and you’ve made role-play a chore.
Look, I get it. In most game systems pre-gen characters are a necessity, because there are so few hours in a convention demo slot. Which is why as a player myself, I quit going to those sorts of slots.
Conversely, the best way to engage players in a new RPG is:
- Let them create their own characters;
- Role-play until the first needed dice roll;
- Explain how dice work for actions;
- Role-play with that knowledge until combat breaks out;
- Explain how actions work in combat;
- Role-play to the adventure’s conclusion;
- Give players a memento of the session—the character they just created, to dream about playing its future adventures.
This is why D6xD6 and Bookmark HP RPG bookmark and biz card character sheets exist. First, to emphasize just how quickly and concisely you can design a character, and second, to fit the unique character you designed in your wallet or a book. I’ve seen countless 8½ x 11 inch character sheets in convention trash cans because they start to bulk out folders, or spill from the backs of books. (Even the D13 RPG is designed for generating characters quickly at the table.)
Running convention events, I’ve seen this approach succeed repeatedly, virtually inevitably. Some free advice from an old hand who just likes to see people succeed and have fun.