First: Please don't double-post.

Second: I don't think giving you ideas for Sanderson's stories would make Stormlight 2 come out any sooner. :P

Third: I actually just posted something which has some advice on this as well as the discussion of Mistborn and Radiants. The bottom line that these are your agents. The spark should come from your mind, from what you want to see. If you're relying on what a groupthink wants to see--which will be full of scattered and frequently directly oppositional concepts--then by definition you're not ready to come up with your own.

Fourth, as I say there: you just joined today. You don't need to be ready to write tomorrow. You won't be writing missions for a while. This isn't a time-critical, world-shifting event. This isn't a paying job or school assignment with a deadline. Don't get sucked in by nonexistent urgency.

Missions aren't the only thing TO the PPC. You don't NEED to have an agent right away. Relax. Read people's missions. Get to know the people here.