Third question: What are Jon Baldwin's projections?
I'm going to presume you're using our rankings and not the official NFL numbers. The league just ranks all teams by total yardage given up and calls it a day, making no effort to account for context. The Packers gave up the most yardage in the league last year, but they also led the league in interceptions, with eight more than any other team, which is a big reason they went 15-1. Don't get me wrong, that was a bad defense, but clearly not the worst in the league.
Our numbers are complicated, but they count not only yards, but also things like sacks and turnovers, and third-down and red-zone performance, as well as strength of schedule. The Chiefs' defense ranked 13th in our system last year, 12th against the pass and 17thagainst the rush, so they'd have to improve quite a bit to make the top five. They didn't generate a lot of negative plays, ranking 29th in stuff rate (percentage of runs that go for no gain or a loss) and 23rd in Adjusted Sack Rate (sacks per pass play, adjusted for down, distance, score, opponent, and other factors). They were also next to last in covering passes to running backs. (Justin Houston finished 80th among linebackers in yards allowed per target in pass coverage.)
It's hard to see where they can improve much in the front seven. Dontari Poe is the only new starter, and most thought the Chiefs reached for him in the first round. Further, Kansas City was very healthy in the front seven last year. Six players here started 14 or more games, and the seventh (Houston) played in every game, though he wasn't always in the starting lineup. Kansas City will probablysuffer more injuries in this unit in 2012, and if anything their overall performance could decline.