Just a quick counter argument against Tom:
Bill was 41-55 as a head coach before Tom Brady stepped. He had a losing record 5 of 6 seasons.
Tom Brady is 172-51 that's less losses than Belichick's first 6 seasons.
For a "system QB" He sure has a lot of individual accomplishments:
11× Pro Bowl (2001, 2004, 2005, 2007, 2009–2015)
4× NFL passing touchdowns leader (2002, 2007, 2010, 2015)
2× Second-team All-Pro (2005, 2015)
4× Super Bowl champion (XXXVI, XXXVIII, XXXIX, XLIX)
3× Super Bowl MVP (XXXVI, XXXVIII, XLIX)
3× First-team All-Pro (2007, 2010, 2012)
3× AFC Offensive Player of the Year (2007, 2010, 2011)
2× AP NFL Most Valuable Player (2007, 2010)
2× NFL Offensive Player of the Year (2007, 2010)
AP & PFWA NFL Comeback Player of the Year (2009)
AP Male Athlete of the Year (2007)
Bert Bell Award (2007)
NFL Alumni Quarterback of the Year (2007)
2× NFL passing yards leader (2005, 2007)
Sporting News Sportsman of the Year (2004, 2007)
Sports Illustrated Sportsman of the Year (2005)
NFL 2000s All-Decade Team
Orange Bowl (2000)
Citrus Bowl (1999)
Rose Bowl (1998)
2× Big Ten champion (1997, 1998)
National champion (1997)
NFL records:
Playoffs (career)
Super Bowl (career)