I am about to (in a couple of weeks) pitch a game I want to GM to a small crowd of people. There is more than one challenge to it, since it's a real-life example.
I am a non-student member of a local university GameSoc - purely as a means to connect with other RPG enthusiast in the area. They do an RPG meetup session at the beginning of the academic year. The formula is quite weird: first you may post a message on their FB wall to advertise your game, giving a short description. At the meeting, GMs take turns, giving 5 minute pitches of their games, essentially similar to the FB posts, but more interactive and in front of a ~800 people audience. The players can then approach any of the GMs and talk, picking what they like. Everything from there is to be sorted by the GM and players - place, time, group size etc.
The community of players is actually quite conservative - I know that at least a handful of old-school dungeon crawls are being run every year, with DnD 1st, 3.5, Pathfinder etc. being the most popular. Last year I managed to pitch a drama/mystery game of Mage the Ascension and got a modest but workable response. Two people approached me at the meeting, with one being very keen (came specifically for this) and one quite sceptical. Later on when we needed reinforcements, a follow-up FB post managed to get the attention of two further players. I think at least one of my past players might want to join the next game, but I can't be sure. However, the majority of the crowd were already committed or investigating a game (DnD, you guessed), when it came to my turn.
This year I'd like to pitch a courtly intrigue game, based on Fate system, which I already mentioned here and here. In short, I'd like the game to look and feel like Game of Thrones, but in a world that I'll build together with players and with players driving the narrative in an open, sandboxy way, with me only giving the PCs occasional challenges.
However, the above does not go well with the fact that I have to present the game. Games where the plot is defined by players are likely to be dismissed as raw and vague game concepts. There is some base reluctance, even among players that prefer roleplay and storytelling over system-driven and GM-defined mechanic-heavy games.
How would one prepare and deliver such a pitch?