Since coming back from playing overseas I've been watching a lot of high school baseball and noticed a similar mistake made by most of the catchers I've seen so far. And that is, having their feet too staggered in their secondary stance and some of them even in their primary stance.
Staggering our feet is okay to a certain extent, but if we start getting too staggered we end up making it more difficult to block pitches to our glove side. Why? Because we close off our left side. If we do get into a blocking position we will most likely be late into our blocks and either miss the ball or not be able to control the ball.
While staggering our feet will give us a better chance to throw out a potential base stealer, we don't want to give up our ability to block to both sides of our body.
Throwing out runners is fun and usually how you get noticed as a catcher, so I'm not saying that isn't important. But in terms of controlling the running game, blocking is more important. If you can't control the ball, you can't control the run game.