That doesn't seem like a bad idea actually. Text based game are not too popular at the moment by all the better because it has space to grow, especially as a jam. And, for me, it's refreshing to move the focus from visuals to just gameplay and story elements.
Hello, this jam is something fresh !, for me it's the first time I'm writing so much for a game, it's a perfect training for narrative games. I think it would be great to have it monthly.