Just- One thing that makes me slightly afraid. Call it battle scars from Ragnarok Online and Ultima Online and such similar things but:
I always hold a deep fear of how such 'dynamic' events can deeply disrupt players who simply don't want anything to do with it. I can't really give it an answer to how to handle it, let's just say that this is a thought that continuously makes me think wether such broad-ranging dynamic events are a good idea or not.