i think that the two quarterbacks are quite different. edwards seemingly had superior physical skills to fitzpatrick, but was either unwilling to take risks or unable to process information quickly enough to go downfieldd. fitzpatrick, while physically less gifted than edwards, seems to process the information very quickly and is definately willing to take those risks.
also, ryan fitzpatrick is well respected by his teammates and coaching staff, is a good leader and has all the intangibles you want at the position, edwards seemingly was not wired that way.