Now, back to the actual questions.
Yes - lots of hand-waving. But this game handles it SO WELL that it's not a problem. I can see it being an issue for a game master who has very little or no experience, but in the hands of someone who knows storytelling, cinematics, or even someone who just has a lot of experience running games, then this is fine.
Then again, I'm used to pulling Difficulty Numbers out of my butt on the fly - especially for CyberPunk, and thus Feng Shui isn't too difficult to handle for me.
For epic campaigns, you'd have to ask Jim Zub (artist for Udon studios) - he ran a mega-campaign of Feng Shui that lasted at least a year of weekly sessions.