First, your adventuring party was a lot more than four or five people, and when everyone needs something from you it slows things down. Having two of us helped, but when one doesn't know what the other is doing that can cause more problems. I think one of the unexpected advantages of Mystic Crossroads has been that most interactions don't require GM intervention. The rules covered most player vs. player circumstances so calls for a ref are fewer than other games I've seen.
Second, since you need someone play every Non-Player Character you have to limit your NPCs to the bare minimum. You can pull player away from their own Characters to a degree, but that's not usually what they came to play, and you want everyone to have a good time and get what they came for. That generally means no invading armies of ogres or complex plots to work through, or does it? What we've tried to do is select from the PCs that are already in roles we'd use an NPC for and feed them information that is important for what we hope to transpire in the game. In the best circumstances you get the best of both worlds; all players can be PCs while those supporting NPC spots are filled.
What I learned is not to overcommit to a storyline or single crawl. I can't own the story I think is going to happen, because it will never happen the way I expect. I can't leave NPCs in the woods waiting for PCs who won't show. Instead I have to start the ball rolling and just see what people do. NPCs have to be characters just like everyone, only I get to write their motives and objectives instead of a player. That's when they become "real", making their own decisions and interactions unscripted. There's a point where players write the story for me and I just have to pay attention to what happens and build from there. I have to be ready to change direction and keep a good plot going.
|from Shards of Orn larp|