Every year the Dallas Morning News ranks the special teams units in each team in the NFL. These are very respected and influential rankings. Here is the criteria they use.
The NFL's 32 teams are ranked in 22 kicking-game categories annually by The Dallas Morning News with points assigned in each category according to their standing (one for the best through 32 for the worst). Here are the composite standings:
It will likely come as no surprise, but the Jets ranked 31st in the league with 456 points. San Diego with 490.5 points was the only team that rated worse. Contributing to the ranking was the league worst 24 points the Jets allowed on special teams.
We are not breaking any ground here. By the eyeball test, special teams looked atrocious for most of the season. With better play, the Jets might have had an even better season than their surprise 10-6 year and perhaps made the Playoffs. Bobby April paid for the performance with his job.
Finally we have a way to quantify how poor the performances were.