Apparently these survey things work. The MTA did a survey and they found out exactly what any rider could have told you. The trains are too crowded!

The report card from the MTA

Now this is a tough one to solve! There's only one big line going through the heart of Queens to Manhattan. The 7 is already the most frequent train, and the longest number of cars, and the bench format seating already accomodates the most total passengers...

The NYT reports that they are going to add more non-peak hour 7 trains (since they are already maxed out on peak frequency).