A couple of years back I ran a game of Dungeons & Discourse. It’s based on the brilliant web comic, Dresden Codak. It ran very smoothly, but mostly thanks to good luck and excellent players, not because of any brilliant design on my part.
I used Donjon as the rules, and that worked surprisingly well. Donjon is designed for that kind of off-the-top-of-your-head kind of wild speculation Dungeons & Discourse seems to call for.
The only thing I wasn’t too happy about was the magic system. While I liked the idea of coming up with your own spells (like using Marxist rhetoric to free people of their capitalist mindset – which is what happened in the first game), and while it seemed to be an essential part of the Dungeons & Discourse feel, the system Donjon has for magic seemed a bit lacking.
First of all, it takes time. You roll the dice twice to get to where you want to be. While that is by no means excessive and may be what you want in some games, it does seem to stop the flow of the game in this case. And you don’t want that, when you’re coming up with crazy ideas. Also, while one person is waiting for the spell to finish, everyone else gets to do something interesting. That is a less than an ideal way of spending your time sitting around the gaming table.
Second, it is complex. If I will run Dungeons & Discourse again, it will probably be at Ropecon. I won’t have the time to go through very complex rules during the game session, and I can’t assume that people playing the game will know the rules in advance. The rules need to be intuitive enough to be usable after a very short explanation, even if understanding the full scope of them takes some getting used to.
So, I need to be able to drop some of the complexity of the magic rules to a level that corresponds with the rest of the rules, so that the magic system will work intuitively when you understand the rest of the game
But that is not so easily done. Either I go questing online for modifications people have made for the game or I try coming up with my own solutions - probably a bit of both.