In my opinion, the NFL has become more pass friendly because defensive backs can't play a physical in coverage as they used to like in the days of Deion Sanders, Terry McDaniel, Rod Woodson, and Ronnie Lott (just to name a few). In that era was when the running game became more effective because the DBs were playing so physically tough and it was hard for receivers to get open.
Now days, DBs can barely touch the WRs which allows them to get open easier and the passing game is more effective.
The run is still defended the same way it always was...plus if you touch certain QBs (Brees, Brady, either of the Mannings, Rodgers, Rivers to be specific) you still get penalized for roughing the passer. Other QBs are only that fortunate when playing the Raiders...Big Ben was in a game where they BROKE HIS NOSE on a late hit and no flags were thrown (and he surprisingly returned). Plus Rich Gannon was speared by Siragusa's helmet in the AFC championship in the 2000-01 playoffs which in my eyes cost us a superbowl!!!