First of all, Ben Roethlisberger was brilliant tonight. He used his legs to buy time, and then made accurate throws downfield. I'm not sure how different things would've been had Ravens cornerbacks Samari Rolle and Chris McAlister played.
There definitely wouldn't have been as many dropped coverages. Ravens cornerbacks David Pittman and Derrick Martin are second-year players who weren't ready for this type of stage.
The one thing the Ravens did was hold the Steelers' vaunted rushing attack in check, but it didn't really matter. Roethlisberger could do anything he wanted against the Ravens. His line did a pretty nice job of giving him time.