6.6 YPA is
not managing the offense, IMO. You need a much higher YPA if you expect to win in the NFL. YPA is one of the most important stats for the offense, IMO.
http://www.behindthesteelcurtain.com/2013/7/8/4501716/nfl-statistics-yards-per-attempt
Just go back and look at the recent SB winners. All of them have QB's that were at or very near the top of YPA. Flacco might be considered an exception but if you look at his YPA passing during the playoffs, you'll find it shoots up to 9.05. Roethlisberger was similar in 2008. His YPA in the regular season was okay but it shot up in the playoffs when it mattered most.
A YPA in the 6's won't cut it- not if you want to do more than just make a playoff game and then lose. So you'd better hope our offense is quite a bit more "flashy and high powered" if you want to ever win the SB. Just running it with a good defense isn't enough. You still have to have the relatively high YPA passing game.