It doesn't do anything but put a target on the team. There is a reason why most coaches don't give or want their players to give the other teams bulletin board material.
I don't care what the experts predicted. Half of them have no idea what they are talking about. The Jets had the talent to be in the 6 to 8 win range. Going 8-8 with that team doesn't make him a great coach.
It's great that they were able to win some playoff games when they got in, but all those wins came in only 2 appearances and resulted in nothing. I might give a coach (who doesn't make the playoffs often) a pass if he won the Super Bowl in one of those appearances, but not when you come out of it with nothing to show for it. When you only make the playoffs 2 out of 5 years (with one of those years basically a gimme playoff birth), I can't consider you one of the best coaches in the NFL. Let's take a look at where Rex ranks in playoff apps compared to other coaches.
Playoff apps since 2009:
Bill Belichick 5
Mike McCarthy 5
John Harbaugh 4
Marvin Lewis 4
Mike Smith 3
John Fox 3
Sean Payton 3
Jim Harbaugh 3 (Only been in the league since 2011 and has more playoff apps)
Pete Carrol 3 (Only been in the league since 2010 and has more playoff apps)
Andy Reid 3
Mike Tomlin 2
Gary Kubiak 2
Jim Caldwell 2
Rex Ryan 2
Tom Coughlin 1
Only Coughlin has fewer playoff apps, but he won a Super Bowl with that appearance.
All you know is what Rex has done with a completely different roster. You don't know what he can do with this roster. Philbin has exhibited some weakness in his two seasons as HC, but I'm confident he can lead this team to a playoff birth. He will have another shot at Rex in week 17. We'll see what happens.
You do know the Giants went 5-0 against AFC East teams in 2011 right?
Ask anyone else which team in New York has been better over the last 5 years, and the clear answer will be the New York Giants.