The Atlanta Falcons have been busy this spring. They have fleshed out their defense with several new contributors in the hopes of raising the floor and establishing some more consistency for Kevin Stefanski’s first season as head coach.  As we approach the franchise’s organized team activities and mandatory mini-camps, Falcons OnSI took a look at the biggest questions still facing the organization.  Defensive Line – Do They Have Their Run-Stopper? The Falcons struggled in run defense last season, finishing No. 27 in expected points added (EPA) per rush. On top of those issues is the fact that Atlanta lost some of their better run defenders in free agency – mainly David Onyemata.  Overall, their rush defense was not terrible on a week-to-week basis. Aside from one dreadful performance against the Colts in Berlin, the Falcons allowed an average of 113 yards rushing per game. Omitting that one game would have lifted them into the top half of the league.…