Fitzpatrick in 2015 had 31 touchdowns and 15 picks, with an 88.0 rating (partly because he completed just 59.6 percent of his passes). So it's not an apples-to-apples comparison here with McCown. Bringing Fitzpatrick back for 2016 turned out to be a mistake. Don't expect the Jets to give McCown that kind of contract ($12 million) next summer. Remember, McCown is 38 years old. He might not be back with the Jets at all in 2018. They'll probably draft or sign a quarterback next offseason.
The trading up part obviously depends on where the Jets are positioned in the draft.