When the Rangers signed Staal and Girardi to their extensions there was not a huge outcry from the fans? So why wouldn't there be the same angst with Yandle by the end of the first or second year of the contract? There were more positive than negative feelings about Girardi than Staal. Now both of them are blights to the organization.
If I remember correctly, only a small minority were against extending both of them. The mindset of the team was different. The Rangers were chasing a Cup. Who would have stepped in and eaten Girardi's minutes in 2014? Staal's in 2015? Hindsight is 20/20.
I don't think many people saw Girardi trending down as severely as he has. I think most expected him to drop off a bit from a top pairing minutes mucher to a 2nd pairing defenseman, but who saw him going from a borderline top pairing defenseman to a bottom pairing one a season later? Girardi's demise has been sudden and shocking.
Staal is what he is. He really hasn't been dominant since his eye injury and concussion from 2012-13. He can still be a good #3-4 option when paired with a good transitional partner that can move the puck well. He was more inconsistent this past season, but his overall level of play didn't really decrease that much. He still has value in a trade if he'll waive his no move.
Yandle would be more of the same. Remember Wade Redden? Redden got a lot of hate here, but I blame Sather for him. He got paid like a top pairing defenseman when it was obvious that he was a middle pairing defenseman. Yandle puts up the points, but half of the Rangers fanbase will be cursing him for his defensive mistakes, and he makes plenty.
The Rangers shouldn't be signing anyone over 28 to a long term contract. Period. Re-tool and see what you have in 2-3 years time, and go from there.