That's one aspect of it, yes. But it's hardly what defines it. It's much more defined by its social commentary and critiques in general, which do not inherently rely on raunchy humor punching down.
In your opinion, sure. But that doesn't mean that's an accurate reflection of what I believe or what Rockstar is aiming for based on this early leak.
Not at all. The Timmy's of the world can be full participants in this, just as Timmy is a full participant in South Park and simply a one-note joke. He's a fairly fleshed out character and wasn't limited to a one-note joke.