I really love this idea and I'd definitely join it; I've more than once considered taking games that are in systems I find too complicated and/or find the base game problematic and reworking them into an engine that's a lot lighter and simpler. I agree that Dungeon World is kinda a "cover" for D&D, and Urban Shadows is one for the World of Darkness, and that's the sort of thing I'd be really into.