To me, "Flaws" means tons of penalties, dropped passes, running backs who fumble, linebackers who miss tackles, etc. While some of that is certainly happening, I would not say this kind of play is a defining characteristic of the 2019-20 Bills. They are a pretty disciplined group overall, they just don't connect on flashy bomb passes or get lots of sacks. They don't have any real superstars on offense or defense. They have a conservative coaching staff.
If those are flaws, I must be reading about football in Forbes freaking magazine.