Can't we all get along and say it together: "WE DO NOT KNOW YET."
I remember a second year QB who averaged a pathetic 5.79 net yards/attempt... took 41 sacks on just 413 dropbacks... his name was Tom Brady: http://www.pro-football-reference.com/players/B/BradTo00.htm
I remember a rookie with a QBR of 71 (to EJ's 78) who turned out OK... his name was Peyton Manning: http://www.pro-football-reference.com/players/M/MannPe00.htm
I recall a guy whose ANY/A were just 5.6, and who took 43 sacks in just 480 attempts, a total bum... who became HOFer Jim Kelly: http://www.pro-football-reference.com/players/K/KellJi00.htm
Does this mean EJ will be as good as these guys?
No.
But can we give EJ a chance? http://www.pro-football-reference.com/players/M/ManuEJ00.htm