How does Matt improve by us running the ball more? Using him less means he will improve?
Do you not understand that any quarterback who has an effective running game at his disposal will be more successful overall?
Our offense is built almost entirely around the boot and play-action. If Arian is gashing people for 5 YPC, Matt's job becomes that much easier.
The point is that Matt is a good QB on his own merits, he didn't need a running game to play well, as we found out in 2009. So, add in a deadly ground game, and we become even more successful. We can then control the clock, which helps our defense, and our redzone scoring percentage also goes up. RZ% is a stat that is almost always reflective of how good a team's running game is, and never a reflection of quarterback play.
This has been proven true for almost every Superbowl winning team ever. Even now during the era of the pitch and catch. You simply cannot win a Superbowl unless your team is somewhat balanced. Peyton Manning went bananas in 2004, 2005, and 2006, but it wasn't until the Colts had their best running game and defense (2007) that he finally won a superbowl. New England's Superbowls came on the backs of mostly their running game (2001 and 2004) and defense (2003 and 2004). Tom Brady's historic seasons proved ultimately fruitless in the pursuit of a championship (2008, 2012). The two teams that had almost no running game that won a Superbowl, the Saints and Packers, had decidedly outstanding defenses.
So, in conclusion, we're lucky we have a QB that can throw for almost 5000 yards and lead a top 5 offense on his own. But wins, not stats, are the goal here. We'll get to our championship quicker with a more balanced team.