I think the only way to call Rory overrated is to compare him to Tiger. No other player since Tiger has accomplished as much at a young age. Is he the next Tiger? Of course not, but he's the closest thing we've seen to him since.
A pitch shot is where you have to pitch the ball up into the air to get it over something. Whether that be a bunker, water, rough, or undulations in a green.
A chip shot is used around the green with low trajectory and more roll, usually with a lower lofted club (but not necessarily).